System and method for providing uplink inter cell interference coordination in a network environment

ABSTRACT

A method is provided in one example embodiment and may include determining one or more uplink inter cell interference coordination (ICIC) parameters for a plurality of cells based, at least in part, on feedback information associated with the plurality of cells; exchanging interference information between neighboring cells; and scheduling uplink transmissions for user equipment served by the neighboring cells based, at least in part, on the uplink ICIC parameters and the interference information exchanged between neighboring cells. A method is provided in another example embodiment and may include determining a ratio relating a first portion of a frequency spectrum for assigning fractional frequency re-use resources to a second portion of the frequency spectrum for assigning re-use one resources; and updating the ratio relating the first portion and the second portion of the frequency spectrum to optimize throughput rates for the plurality of user equipment across the plurality of cells.

RELATED APPLICATION

This application is a continuation (and claims the benefit of priorityunder 35 U.S.C. §120) of U.S. application Ser. No. 14/686,598, filedApr. 14, 2015, entitled “SYSTEM AND METHOD FOR PROVIDING UPLINK INTERCELL INTERFERENCE COORDINATION IN A NETWORK ENVIRONMENT,” InventorsRitesh K. Madan, et al. The disclosure of the prior application isconsidered part of (and is incorporated in its entirety by reference in)the disclosure of this application.

TECHNICAL FIELD

This disclosure relates in general to the field of communications and,more particularly, to a system and method for providing uplink (UL)inter cell interference coordination (ICIC) in a network environment.

BACKGROUND

Networking architectures have grown increasingly complex incommunications environments, particularly mobile wireless environments.Mobile communication networks have grown substantially in subscriberbase as end users become increasingly connected to mobile wirelessenvironments. As the number of mobile subscribers increases, efficientmanagement of communication resources becomes more critical. In someinstances, resources are allocated for uplink transmission by userequipment served by a particular cell radio. Uplink transmissions aretypically scheduled for user equipment served by the particular cellradio. As the number of user equipment (e.g., the number of subscribers)increases, the possibility of inter cell interference also increases,which can lead to inefficient performance of the user equipment and forthe network. Accordingly, there are significant challenges in providinguplink ICIC for mobile communication networks, particularly with respectto small cell networks, which often include multiple small cell radiosprovided in close proximity to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

To provide a more complete understanding of the present disclosure andfeatures and advantages thereof, reference is made to the followingdescription, taken in conjunction with the accompanying figures, whereinlike reference numerals represent like parts, in which:

FIG. 1A is a simplified block diagram illustrating a communicationsystem to facilitate providing uplink ICIC in a network environmentaccording to one embodiment of the present disclosure;

FIG. 1B is a simplified schematic diagram illustrating example detailsassociated with an example resource block that can be associated withuplink transmissions in accordance with one potential embodiment of thecommunication system;

FIG. 1C is a simplified schematic diagram illustrating example detailsassociated with an example frequency spectrum that can be associatedwith the communication system in accordance with one potentialembodiment of the communication system;

FIG. 2 is a simplified block diagram illustrating an example use case ofcell radios associated with the communication system in accordance withone potential embodiment of the present disclosure;

FIG. 3 is a simplified flow diagram illustrating example operationsassociated with providing uplink ICIC in a network environment inaccordance with one potential embodiment of the communication system;

FIG. 4 is a simplified flow diagram illustrating example operationsassociated with determining user equipment specific feedback for uplinkICIC in accordance with one potential embodiment of the communicationsystem;

FIG. 5 is a simplified flow diagram illustrating example operationsassociated with determining cell specific feedback for uplink ICIC inaccordance with one potential embodiment of the communication system;

FIGS. 6A-6C are simplified flow diagrams illustrating example operationsassociated with setting interference power spectral density (PSD) levelsfor interference mitigation in accordance with one potential embodimentof the communication system;

FIG. 7 is a simplified flow diagram illustrating example operationsassociated with determining one or more uplink ICIC parameters that canbe used to provide uplink ICIC in accordance with one potentialembodiment of the communication system;

FIG. 8 is a simplified schematic diagram illustrating other exampledetails associated with an example frequency spectrum that can beassociated with the communication system in accordance with onepotential embodiment of the communication system;

FIG. 9 is a simplified flow diagram illustrating example operationsassociated with providing resource adaptation for interferencemitigation in accordance with one potential embodiment of thecommunication system;

FIG. 10 is a flow diagram illustrating other example operationsassociated with providing resource adaptation for interferencemitigation in accordance with one potential embodiment of thecommunication system;

FIG. 11 is a flow diagram illustrating yet other example operationsassociated with providing resource adaptation for interferencemitigation in accordance with one potential embodiment of thecommunication system; and

FIGS. 12A-12C are simplified block diagrams illustrating additionaldetails associated with various potential embodiments of thecommunication system.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

A method is provided in one example embodiment and may includedetermining by a central management entity one or more uplink inter cellinterference coordination (ICIC) parameters for a plurality of cellsbased, at least in part, on feedback information associated with theplurality of cells, wherein the feedback information is associated, atleast in part, with signal strength information associated with theplurality of cells and wherein the uplink ICIC parameters include, atleast in part, a low interference power spectral density (PSD) level anda medium interference PSD level; communicating the uplink ICICparameters to each of the plurality of cells; exchanging interferenceinformation between neighboring cells of the plurality of cells whereinthe interference information includes, at least in part, interferenceguarantees for certain transmissions between each neighboring cell ofthe plurality of cells based on the low interference PSD level and themedium interference PSD level; and scheduling uplink transmissions foruser equipment served by the neighboring cells based, at least in part,on the uplink ICIC parameters and the interference information exchangedbetween neighboring cells. In some instances, the uplink transmissionscan be scheduled in at least one of a re-use one portion and afractional frequency re-use (FFR) portion of a frequency spectrumavailable for the uplink transmissions.

In some instances, determining the one or more uplink ICIC parameterscan further include setting the low interference PSD level, wherein thelow interference PSD level is set to allow a certain percentage of celledge user equipment served by each of the neighboring cells to achieve aSignal-to-Interference-plus-Noise Ratio of approximately 7 decibels(dB). In other instances, determining the one or more uplink ICICparameters can additionally include setting the medium interference PSDlevel, wherein the medium interference PSD level is based on an averageinterference level determined for the plurality of cells for all userequipment served by each of the plurality of cells.

In yet other instances, determining the one or more uplink ICICparameters can additionally include determining a number of neighboringcells for each of the plurality of cells based, at least in part, on thesignal strength information, wherein one or more cells are determined tobe neighboring another cell if their signal strength is above a certainthreshold; determining a number of resources for uplink transmissionsfor the FFR portion of the frequency spectrum, wherein the number ofresources for the uplink transmissions for the FFR portion of thefrequency spectrum is inversely proportional to the number ofneighboring cells for each of the plurality of cells; and determiningfractions of total resources for uplink transmissions for resource blockregions of the re-use one portion and the FFR portion of the frequencyspectrum.

In some cases, exchanging interference information between neighboringcells can include distributing High Interference Information (HII)messages over X2 interfaces between neighboring cells to coordinate highinterference resource block (RB) guarantees and low interference RBguarantees for the FFR portion of the frequency spectrum based, at leastin part, on the number of resources determined for uplink transmissionfor the FFR portion, the fractions of total resources for uplinktransmissions, the low interference PSD level and the mediuminterference PSD level.

In some cases, the signal strength information can include ReferenceSignal Received Power (RSRP) information and the method can includereceiving by a particular cell of the plurality of cells RSRPinformation from each of a plurality of user equipment (UE) served bythe particular cell, wherein the RSRP information received from each UEincludes, at least in part, a serving cell RSRP value for the particularcell and one or more neighboring cell RSRP values for one or moreneighboring cells of the particular cell. In some instances, the methodcan further include determining a number of UEs connected to theparticular cell; determining a number of UEs for which one or moreneighboring cell RSRP values are above an RSRP threshold; and includingin the feedback information: the number of UEs connected to theparticular cell; the number of UEs having one or more neighboring cellRSRP values above the RSRP threshold; the serving cell RSRP value foreach of the number of UEs having one or more neighboring cell RSRPvalues above the RSRP threshold; and a cell identifier and acorresponding RSRP value for each of the one or neighboring cell RSRPvalues above the RSRP threshold. In other instances, the method caninclude determining one or more relative interference values for each ofone or more neighboring cells of the particular cell for each of one ormore UEs connected to the particular cell, wherein the each relativeinterference value is based on the serving cell RSRP value and aneighboring cell RSRP value for each of the one or more neighboringcells as received from each of the one or more UEs; determining whethereach relative interference value is above a relative interferencethreshold; ordering each relative interference value that is above therelative interference threshold in a predetermined order; determining ahighest relative interference value for each of the one or moreneighboring cells that is above the relative interference threshold; andincluding in the feedback information the highest relative interferencevalue and a cell identifier for each of the one or more neighboringcells that is above the relative interference threshold according to thepredetermined order.

Another method is provided in another example embodiment and may includedetermining a ratio relating a first portion of a frequency spectrum inwhich fractional frequency re-use (FFR) resources are to be assigned toa second portion of the frequency spectrum in which re-use one resourcesare to be assigned, wherein the FFR resources and the re-use oneresources are associated with uplink transmissions for a plurality ofuser equipment across a plurality of cells in a communication system;and updating the ratio relating the first portion and the second portionof the frequency spectrum to optimize throughput rates for the pluralityof user equipment across the plurality of cells. In some cases, at leastone of determining the ratio or updating the ratio can includemaximizing a total sum of utilities of throughput rates for the userequipment across the plurality of cells for a utility function todetermine an optimum value for the ratio based, at least in part, on oneor more interference power spectral density (PSD) levels associated withneighboring cells of the plurality of cells and wherein the total sum ofutilities of throughput rates for the user equipment can vary based, atleast in part, a plurality of temporary values of the ratio. In variousinstances, the utility function can be associated with a total sum of alogarithmic function (LOG) of average throughput rates for the userequipment; a total sum of a weighted exponential function of averagethroughput rates for the user equipment; or a total sum of averagethroughput rates for the user equipment.

In some instances, maximizing the total sum of utilities as a functionof throughput rates for the user equipment can further include:calculating, by each cell of the plurality of cells, a per cell totalsum of utilities for achievable throughput rates for a plurality of userequipment served by each cell for each the plurality of temporary valuesof the ratio; communicating, by each cell of the plurality of cells, theper cell total sum of utilities for achievable throughput rates to acentral management system for each of the plurality of temporary valuesof the ratio; calculating a total sum of utilities across the pluralityof cells based on the per cell total sum of utilities for each of theplurality of temporary values of the ratio; determining, by the centralmanagement system, a maximum total sum of utilities and a particulartemporary value of the ratio associated with the maximum total sum ofutilities; and setting the ratio equal to the particular temporary valueof the ratio associated with the maximum total sum of utilities.

In some instances, calculating the per cell total sum of utilities forachievable throughput rates for the plurality of user equipment servedby a particular cell can further include: calculating a weighted sum ofthroughput rates achievable for each user equipment served by theparticular cell in relation to a number of resource blocks that can beallocated in a plurality of resource block regions of the frequencyspectrum and wherein the number of resource blocks that can be allocatedin one or more of the resource block regions is varied according to eachof the plurality of temporary values of the ratio; and accumulatingweighted sums of throughput rates achievable for all user equipmentserved by the particular cell according to each of the plurality oftemporary values of the ratio to determine a total sum of utility ofthroughput rates for all user equipment served by the cell for each ofthe plurality of temporary values of the ratio.

In some cases, updating the ratio can further include: determining, byeach cell of the plurality of cells, a first modulation and codingscheme (MSC) for each of a plurality of user equipment served by eachcell in a first resource block region of the frequency spectrum. In somecases, the updating can further include determining, by each cell of theplurality of cells, a first number of resource blocks in the firstresource block region assigned to user equipment that have acorresponding first MCS below a predetermined MCS threshold; anddetermining, by each cell of the plurality of cells, a second number ofresource blocks in a second resource block region assigned to userequipment that have a corresponding first MCS above the predeterminedMCS threshold. In still other cases, updating the ratio can additionallyinclude communicating, by each cell of the plurality of cells, the firstnumber of resource blocks and the second number of resource blocks to acentral management system; increasing the ratio if a low percentile ofthe first number of resource blocks communicated by each of theplurality of cells is below a first predetermined resource blockthreshold; and reducing the ratio if a high percentile of the secondnumber of resource blocks communicated by each of the plurality of cellsis above a second predetermined resource block threshold. In someinstances, the predetermined MCS threshold is associated with apredetermined signal-to-interference-noise ratio (SINR) associated withinterference between neighboring cells of the plurality of cells in thecommunication system.

EXAMPLE EMBODIMENTS

Turning to FIG. 1A, FIG. 1A is a simplified block diagram illustrating acommunication system 100 to facilitate providing uplink (UL) inter cellinterference coordination (ICIC) in a network environment according toone embodiment of the present disclosure. This particular configurationmay be tied to the 3rd Generation Partnership Project (3GPP) EvolvedPacket System (EPS) architecture, also sometimes referred to as the LongTerm Evolution (LTE) EPS architecture. Alternatively, the depictedarchitecture may be applicable to other environments equally. Theexample architecture of FIG. 1A can include users operating userequipment (UE) 112 a-112 d, one or more cell radio(s) 114 a-114 b, aradio access network (RAN) 120, a central management system 122 and aservice provider network 130. As shown in FIG. 1A, each respective cellradio 114 a, 114 b can include a respective resource scheduler 140 a,140 b and central management system 122 can include an interferencemanagement module 150. FIGS. 1B-1C are schematic diagrams illustratingvarious example details that can be associated with communication system100 and will be discussed in conjunction with FIG. 1A.

Each cell radio 114 a-114 b can be associated with a correspondingcoverage area, as indicated by the dashed-line circle surrounding eachcell radio 114 a-114 b. It should be understood that the coverage areasshown in FIG. 1A are provided for illustrative purposes only, and arenot meant to limit the broad scope of the teachings of the presentdisclosure. Any other coverage areas can be provided for cell radioswithin the scope of the present disclosure.

In various embodiments, UE 112 a-112 d can be associated with users,employees, clients, customers, etc. wishing to initiate a flow incommunication system 100 via some network. The terms ‘user equipment’,‘mobile node’, ‘end user’, ‘user’, and ‘subscriber’ are inclusive ofdevices used to initiate a communication, such as a computer, a personaldigital assistant (PDA), a laptop or electronic notebook, a cellulartelephone, an i-Phone™, iPad™, a Google Droid™ phone, an IP phone, orany other device, component, element, or object capable of initiatingvoice, audio, video, media, or data exchanges within communicationsystem 100. UE 112 a-112 d may also be inclusive of a suitable interfaceto a human user such as a microphone, a display, a keyboard, or otherterminal equipment.

UE 112 a-112 d may also be any device that seeks to initiate acommunication on behalf of another entity or element such as a program,a database, or any other component, device, element, or object capableof initiating an exchange within communication system 100. Data, as usedherein in this document, refers to any type of numeric, voice, video,media, or script data, or any type of source or object code, or anyother suitable information in any appropriate format that may becommunicated from one point to another. In certain embodiments, UE 112a-112 d may have a bundled subscription for network access andapplication services (e.g., voice), etc. Once the access session isestablished, the user can register for application services as well,without additional authentication requirements. UE IP addresses can beassigned using dynamic host configuration protocol (DHCP), StatelessAddress Auto-configuration, default bearer activation, etc., or anysuitable variation thereof. In various embodiments, each UE 112 a-112 dcan include one or transmitters and/or receivers (e.g., transceivers)and one or more antenna(s) to facilitate over the air communicationswith one or more cell radios 114 a-114 b.

For FIG. 1A, cell radios 114 a-114 b are logically connected to serviceprovider network 130 and can also be logically connected to adjacentcell radios via an X2 interface, as defined in 3GPP standards. Invarious embodiments, interfaces (e.g., the X2 interface) and/or a seriesof interfaces can be provided in communication system 100, which canoffer mobility, policy control, interference mitigation functions, etc.for various elements of communication system 100. For example,interfaces can be used to exchange point of attachment, location, and/oraccess data for one or more end users, for example, users operating UE112 a-112 d. In various embodiments, resource information, accountinginformation, location information, access network information, networkaddress translation (NAT) control, etc. can be exchanged using a remoteauthentication dial in user service (RADIUS) protocol or any othersuitable protocol where appropriate. Other protocols that can be used incommunication system 100 can include DIAMETER protocol, service gatewayinterface (SGi), terminal access controller access-control system(TACACS), TACACS+, etc. to facilitate communications.

In various embodiments, cell radios 114 a-114 b can be deployed asevolved Node Bs (eNodeBs), which can provide cellular/mobile coveragefor a macro cell network, or can be deployed as home eNodeBs (HeNBs),which can provide cellular/mobile coverage for a small cell network. Invarious embodiments, for example, in a macro cell network deployment,cell radios 114 a-114 b can be responsible for selecting a MobilityManagement Entity (MME) within service provider network 130 for sessionestablishment for each UE 112 a-112 d served by a corresponding cellradio, for managing radio resources for each UE 112 a-112 d, and makinghandover decisions for UEs, for example, handover to other cell radios(e.g., eNodeBs and/or HeNBs). In certain embodiments, for example, in asmall cell network deployment, cell radios 114 a-114 b (e.g., deployedas HeNBs) can interface with service provider network 130 via one ormore small cell gateways (not shown), which can be used to aggregateand/or manage sessions for UE connected to the small cell network aswell as managing configurations of cell radios 114 a-114 b. In variousembodiments, each cell radio 114 a-114 b can include one or transmittersand/or receivers (e.g., transceivers) and one or more antenna(s) tofacilitate over the air communications with one or more UE 112 a-112 d.

In various embodiments, each cell radio 114 a-114 b may managescheduling for uplink radio resources for uplink transmissions for eachcorresponding UE 112 a-112 d that the cell radios respectively serve viaeach respective resource scheduler 140 a-140 b. Uplink radio resourcescan be distinguished from downlink resources, as uplink resources may bethose resources transmitted by over an air interface a particular UE(e.g., using one or more combinations of transmitters and/or antenna(s))to be received by its serving cell radio (e.g., using one or morecombinations of receivers and/or antenna(s)) whereas downlink resourcesmay be those resources transmitted over an air interface by the servingcell radio (e.g., using one or more combinations of transmitters and/orantenna(s)) to be received by the particular UE (e.g., using one or morecombinations of receivers and/or antenna(s)). For example, in certainembodiments, assuming UE 112 a-112 b are connected to and currentlyserved by cell radio 114 a, cell radio 114 a, via resource scheduler 140a can schedule uplink resources for uplink transmissions that can beperformed by UE 112 a-112 b. In turn, UE 112 a-112 b can perform uplinktransmissions as scheduled by cell radio 114 a. Typically, uplinktransmissions are scheduled via uplink grants that can be communicatedby a serving cell radio to a corresponding UE. Similar uplinktransmissions can be scheduled for UE 112 c-112 d by cell radio 114 bvia resource scheduler 140 b, assuming UE 112 c-112 d are connected toand served by cell radio 114 b. Note the terms ‘cell radio’ and ‘cell’can be used interchangeably herein in this Specification.

UEs 112 a-112 d are illustrated in FIG. 1A as being located in relativeproximities within the coverage areas of their respective serving cells.For example, as shown in FIG. 1A, UE 112 a can be considered an interiorUE within the coverage area of cell radio 114 a and UE 112 b can beconsidered a cell edge UE within the coverage area of cell radio 114 a.Similarly, UE 112 d can be considered an interior UE within the coveragearea of cell radio 114 b and UE 112 c can be considered a cell edge UEwithin the coverage area of cell radio 114 b. The characterization ofUEs 112 a-112 d is provided for illustrative purposes only and is notmeant to limit the broad scope of the present disclosure. It should beunderstood that UEs can be distributed anywhere within the coverageareas of cell radios within the scope of the teachings of the presentdisclosure.

In various embodiments, determination of whether a given UE is a celledge UE or a cell interior UE can be performed by the cell radio using,for example, the channel quality indicator (CQI) for the UE in thedownlink, via the reference signal received quality (RSRQ) for the UE orby determining the received power for an uplink signal from the UEdivided by the interference in the cell. In certain embodiments, a UEcan be characterized as a cell edge UE if its CQI, RSRQ and/or uplinksignal divided by interference is less than a predetermined threshold.

In certain embodiments, LTE architectures can support multi-user accessusing Orthogonal Frequency-Division Multiple Access (OFDMA), which is amulti-user version of the orthogonal frequency-division multiplexing(OFDM) digital modulation scheme. Multiple accesses are achieved inOFDMA by assigning subsets of subcarriers to individual users. OFDMAallows for simultaneous transmissions from several users served by aparticular cell radio. In certain embodiments, LTE architectures canalso support multi-user access using Single Carrier Frequency DivisionMultiple Access (SC-FDMA), which is similar to OFDMA, but includesadditional precoding.

As a general notion, in LTE architectures, a given serving cell radio(e.g., cell radio 114 a) can schedule uplink transmissions for a givenUE (e.g., UE 112 a) by scheduling physical resource blocks, generallyreferred to as resource blocks (RBs), that are to be transmitted by theUE according to one or more uplink grants, as noted above. For example,using one or more uplink grants, cell radio 114 a can signal to the UE,when it can transmit uplink RBs or resources toward cell radio 114 a.Uplink grants are typically communicated to the UE via a physicaldownlink control channel (PDCCH) maintained between the UE and theserving cell radio. Typically, the PDCCH can be used to communicateinformation related to information downlink (DL) grant(s), uplink (UL)grant(s), power control, system configuration, random access, paging,etc. for UE, as defined in 3GPP standards.

An RB, as defined in 3GPP technical specification (TS) 36.211, istypically represented by a number of resource elements, each of whichcan be allocated within a symbol, for each of a particular subcarrier(e.g., frequency) that can be associated with a particular UE. An RB cangenerally be referred to as a ‘slot’ spanning 0.5 milliseconds (msec) ofa 1 msec subframe. Thus, there are typically two RBs in each 1 msecsubframe. The smallest unit of an RB is a resource element, whichrepresents one subcarrier by one symbol. Thus, a RB can be schematicallyrepresented as spanning a portion of frequencies of system bandwidth(e.g., depending on the number of subcarriers in the RB) across a spanof time (e.g., 0.5 msec) for each symbol included in the RB. For 4G/LTE,the number of subcarriers for an RB is 12, each spanning a 15 kilohertz(15 KHz subcarrier bandwidth), thus each RB represents a 180 KHz portionof system bandwidth. As system bandwidth can vary, such as, for example,between 1.25 megahertz (MHz) and 20 MHz, the number of available RBsthat can be scheduled or allocated across UEs can vary, respectivelybetween 6 and 100. Typically, a 10 MHz bandwidth corresponds to 50available RBs that can be allocated to UEs served by a particular cell.It should be understood that RBs can be uplink RBs or downlink RBs,depending on the device transmitting the RBs.

Referring to FIG. 1B, FIG. 1B is a simplified schematic diagramillustrating an example uplink RB 160 that can be used for uplinktransmissions in accordance with one potential embodiment of thecommunication system. Uplink RB 160 can represents a 0.5 msec slot 164of a 1 millisecond (msec) transmission time interval (TTI) for a numberof symbols 168 spread across a number of subcarriers 166. In variousembodiments, the number of subcarriers 166 is typically 12. In variousembodiments, the number of symbols 168 can depend on the cyclic prefixtype for uplink transmissions (e.g., 12 symbols for normal cyclic prefixor 14 for symbols for extended cyclic prefix). As noted, the smallestunit of a RB is a resource element, shown in FIG. 1B as resource element170, which represents one subcarrier 166 by one symbol 168.

Returning to FIG. 1A, each resource element for each symbol of an RB canbe represented using a number of bits, which can vary depending onmodulation and coding scheme (MCS) selected for uplink transmissions fora given UE. In various embodiments, the MCS selected for uplinktransmissions can be adjusted based on the uplinkSignal-to-Interference-plus-Noise Ratio (SINR) for a given UE. Forexample, a higher SINR for a UE can result in a higher MCS beingselected for the UE, which, in turn can provide for a higher throughputrate for the UE. As provided by 3GPP standards (e.g., TS 36.111), MCSfor uplink transmissions can include Quadrature Phase Shift Keying(QPSK) and Quadrature Amplitude Modulation (QAM) including 16QAM, 64QAMand 256QAM with modulation order increasing from QPSK to 256QAM.

In various embodiments, SINR for a given UE (e.g., any of UE 112 a-112d) can be determined based on Reference Signal Received Quality (RSRQ)as measured by the UE for the Evolved-Universal Terrestrial Radio Access(E-UTRA), the channel quality indicator (CQI) reported by the UE,relative Reference Signal Received Power (RSRP) and/or the receivedsignal strength for an uplink transmission divided by the totalinterference in the cell. Typically, E-UTRA is described in reference tothe air-interface for LTE radio access. As defined in 3GPP TS 36.214,RSRP is the linear average over the power contributions of resourceelements (e.g., within RBs) that carry cell-specific reference signals(CRS) within a considered measurement frequency bandwidth. RSRQ isdefined as the ratio of the number (N) of RBs of the E-UTRA carrierreceived signal strength indicator (RSSI) measurement bandwidth (e.g.,system bandwidth) multiplied by the RSRP divided by the RSSI, generallyexpressed as ‘N*RSRP/RSSI’. In general, UE can measure signal strengthinformation such as, for example, RSRP and/or RSRQ for a serving celland/or non-serving cells (e.g., neighboring cells), if enabled. Incertain embodiments, RSRP and/or RSRQ measurements for neighboring cellsbe enabled for UE 112 a-112 d. As used herein the terms ‘relative RSRP’and ‘relative interference’ can be used interchangeable and can refer toa serving cell RSRP as measured by a given UE subtracted from aneighboring cell RSRP as measured by the UE.

It should be noted that any UE signal strength information can be usedwithin the scope of the present disclosure. In at least one embodiment,for example, for a 3G deployment, signal strength information caninclude Common Pilot Channel (CPICH) energy per chip to total PSD at theUE antenna (Ec/Io) and/or CPICH Received Signal Code Power (RSCP) asdefined in 3GPP standards. In another embodiment, for example, for aWiFi deployment, signal strength information can include Received SignalStrength Indicator (RSSI), Received Channel Power Indicator (RCPT),combinations thereof, or other similar signal strength information.Accordingly, although many of the example embodiments discussed hereinare described with reference to RSRP and/or RSRQ signal strengthinformation, it should be understood that signal strength information asdiscussed for the various embodiments described herein can cover amultitude of access network types including both 3GPP and non-3GPPaccess networks.

In certain embodiments, channel quality indicator (CQI) reported by a UEcan be used to determine downlink SINR by using the CQI reported for agiven UE as a proxy for determining the downlink SINR. Generally, theCQI reported by a UE is essentially the MCS at which the cell radio towhich the UE is connected needs to transmit packets to the UE such thatthe UE will receive packets at a 10% Block Error Rate (BLER). If anAverage White Gaussian Noise (AWGN) channel is assumed for the UE, anSINR can be determined that will lead to a 10% BLER based on the MCSchosen by the cell radio for downlink transmissions to the UE via thePhysical Downlink Shared Channel (PDSCH), which carries data transportblocks to the UE. Generally, each MCS from which the cell radio canchoose for downlink transmissions can be mapped to one or more SINRvalues or a range of SINR values, thereby enabling SINR determinationsusing the MCS chosen for downlink transmissions. Although UEmanufacturers often implement different receivers, etc. for theirequipment, which can lead to non-one-to-one MCS to SINR mappings, CQIcan be used to determine an approximate SINR for a given UE based on theassumption that, as SINR increases for a UE, CQI can also increasebecause the UE can decode higher order modulation schemes while stayingwithin the 10% BLER threshold. It should be understood that, under anassumption of uplink and downlink symmetry for a given UE, uplink ordownlink SINR can be used for various embodiments described herein.

Returning to FIG. 1A, central management system 122 can further includeinterference management module 150, which can, in various embodiments,aid in coordinating uplink resource scheduling between cell radios 114a-114 b for UE 112 a-112 d. In various embodiments, central managementsystem 122 can be deployed as any central management entity, such as,for example, an Operations, Administration and Maintenance (OAM) entity,a Radio Management System (RMS), a Radio Resource Manager (RRM), aSelf-Organizing Network (SON) management system, combinations thereof orthe like. In certain embodiments, an RMS can be used in conjunction withsmall cell deployments, for example, to configure cell radios 114 a-114b according to a particular communications protocol (e.g., technicalreport (TR) 069) and data model (e.g., TR-196 version 2). In certainembodiments, a SON management system can have visibility of one or moreparallel networks such as, for example, a macro cell network, a smallcell network, a wireless local area network (WLAN) and can be used tocoordinate radio resource for different UE among co-deployed parallelnetworks (e.g., having overlapping or neighboring coverage areas fordifferent technologies). In essence, a SON management system may providea system-wide view of communication system 100 and can thereforeintelligently provision resources among different communication networksin the communication system. Accordingly, central management system 122can be configured to interface with any element or node of communicationsystem 100 via one or more logical interfaces. In various embodiments,central management system 122 can be deployed within service providernetwork 130, within cloud-based service (e.g., in a centralized SON(cSON) architecture) and/or can be deployed in a service network for aparticular deployment, such as, for example, in an enterprise small celldeployment.

RAN 120 is a communications interface between UE 112 a-112 d and serviceprovider network 130. In various embodiments, depending on deployment,one or more cell radio(s) 114 a-114 b can be deployed in RAN 120 toprovide macro and/or small cell mobile/cellular coverage for UE 112a-112 d. In general, small cell networks are comprised of multiple smallcell radios, which can provide proximate coverage to users in anenvironment in which macro network coverage may be limited or interfered(e.g., within a building, structure, facility, etc.). Typically, smallcell radios operate at lower radio power levels as compared to macrocell radios. Small cell radios can be connected using a standardbroadband digital subscriber line (DSL), internet or cable service intoservice provider network 130 via one or more small cell gateways. Callscan be made and received, where the signals are sent (potentiallyencrypted) from a given small cell radio via the broadband Internetprotocol (IP) network to one of the service provider's main switchingcenters.

Thus, RAN 120 may provide one or more coverage areas for servicingmultiple end users and for managing their associated connectivity. Thecommunications interface provided by RAN 120 may allow data to beexchanged between an end user and any number of selected elements withincommunication system 100. For example, RAN 120 may facilitate thedelivery of a request packet (e.g., request for service(s)) generated bya given UE (e.g., UE 112 a) and the reception of information sought byan end user. In various embodiments, RAN 120 may include 3GPP accessnetworks such as, for example, Global System for Mobile Communications(GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network(GERAN), generally referred to as 2G, and Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access Network(UTRAN), generally referred to as 3G, and/or evolved UTRAN (E-UTRAN),generally referred to as 4G, Long Term Evolution (LTE) or LTE-Advanced(LTE-A). In various embodiments, RAN 120 may include non-3GPP IP accessnetworks such as digital subscriber line (DSL), Cable, WLAN (e.g.,Wireless Fidelity (WiFi), Worldwide Interoperability for MicrowaveAccess (WiMAX)) or the Internet. RAN 120 is only one example of acommunications interface between an end user and service providernetwork 130. Other suitable types of communications interfaces may beused for any appropriate network design and, further, be based onspecific communications architectures in accordance with particularneeds.

Service provider network 130 represents a series of points or nodes ofinterconnected communication paths for receiving and transmittingpackets of information that propagate through communication system 100.In various embodiments, service provider network 130 can be configuredaccording to 3GPP standards to include one or more elements of anEvolved Packet Core (EPC) in order to provide services (e.g., voice,data, multimedia, etc.) and interconnectivity to UE 112 a-112 d to oneor more packet data networks (e.g., the Internet). Service providernetwork 130 may offer communicative interfaces between UE 112 a-112 dand selected nodes or elements in the network, and may be any local areanetwork (LAN), wireless local area network (WLAN), metropolitan areanetwork (MAN), wide area network (WAN), virtual private network (VPN),Intranet, extranet, or any other appropriate architecture or system thatfacilitates communications in a network environment. Communicationsystem 100 may implement a user datagram protocol (UDP)/Internetprotocol (UDP/IP) connection and use a transmission control protocol(TCP/IP) communication language protocol in particular embodiments ofthe present disclosure. However, communication network may alternativelyimplement any other suitable communication protocol for transmitting andreceiving data packets within communication system 100.

Before detailing some of the operational aspects of FIG. 1A, it isimportant to understand common characteristics of uplink interferencethat can occur in mobile communications networks. The followingfoundation is offered earnestly for teaching purposes only and,therefore should not be construed in any way to limit the broadteachings of the present disclosure.

Uplink RBs can be transmitted by a given UE (e.g., UE 112 a) using aPhysical Uplink Shared Channel (PUSCH), a Physical Uplink ControlChannel (PUCCH) or a Physical Random Access Chanel (PRACH). Uplinktransmissions by UE can cause interference, typically referred to aspower spectral density (PSD) interference or interference PSD, to aparticular serving cell radio and/or to one or more neighboring cellradios. Interference, typically, represented using the symbol ‘I’, canbe expressed as interference over thermal noise (loT), which is theratio of interference PSD to thermal noise PSD. Thermal noise PSD, asdefined in 3GPP TS 26.214, is the white noise PSD on the uplink carrierfrequency multiplied by the uplink system bandwidth.

The transmission of uplink RBs by a given UE can cause interference PSDto its particular serving cell and/or to one or more neighboring cells.For LTE, Release 9 of 3GPP specifications define different interferencemitigation schemes such as, for example, interference reduction andinter cell interference coordination (ICIC). Interference reduction istypically associated with optimizing coverage and capacity for anetwork. ICIC is typically associated with the management of radioresources to mitigate inter cell interference. In the frequency domain,ICIC is used to manage the allocation of RBs between cells in order tocoordinate the use of frequency domain resources.

In particular, frequency domain ICIC can be used to mitigate inter cellinterference with neighboring cells for UEs located at the edge of acoverage area of a given serving cell (e.g., cell edge UEs) that mayhave resources allocated thereto, which can interfere with theneighboring cells. Solutions for ICIC often involve interferencemitigation through either orthogonal transmissions, which are typicallyassociated with fractional frequency re-use (FFR), or Multiple InputMultiple Output (MIMO) schemes, which are typically dependent on numberof antennas configured for a UE.

Typically, semi-orthogonal transmissions associated with FFR can provideinterference mitigation by partitioning the frequency spectrum (e.g.,system bandwidth) available to each cell radio such that each cell usesa spectrum of frequency which does not overlap with a neighboring cellor such that RBs allocated to cell edge UEs for a particular servingcell do not overlap with RBs allocated to cell edge UEs for anyneighboring cells. The term ‘semi-orthogonal’ indicates that on one RB,one cell lowers interference to a neighboring cell while the neighboringcell uses higher power. This differs from orthogonal transmissions,which can be a special case in which the first cell makes aninterference of zero (e.g., does not use the RB at all).

Semi-orthogonal schemes typically involve a static partitioning of thefrequency spectrum for FFR, which can be highly inefficient becausethere may be a large number of UEs on a cell edge but not enoughresources are set aside for FFR where neighboring cells' cell edge UEsare scheduled on non-overlapping portions of the spectrum or in caseswhere no or a minimal number of cell edge UEs may be served by a givencell radio (e.g., in cases where the spectrum is partitioned for celledge UEs). The spectrum allocated to FFR might be wasted or there maynot be enough spectrum for FFR, which can lead to poor utilization ofresources when cell edge UEs are served. In other cases, the number ofinterfering neighbors may change, which could also lead to inefficientuse of system bandwidth for systems having static FFR configurations.FFR frequency allocation schemes can be distinguished from re-use onefrequency allocation schemes in which the entire frequency spectrum canre-used by each cell for allocating resources to all UEs, which areserved as the same transmit power per RB (e.g., having equivalently thesame power spectral density). However, in deployments that rely only onre-use one schemes, interference is typically high at the edges ofneighboring cells.

In accordance with various embodiments described herein, communicationsystem 100 is configured to provide a system and method to facilitateinterference mitigation for uplink ICIC in a network environment throughthe use of information exchanges between each cell radio 114 a-114 b anda central management entity (e.g., central management system 122) andbetween each cell radio 114 a-114 b via the X2 interface. Theinformation exchanges may provide for adaptive resource allocationbetween neighboring cell radios in order to schedule uplink UEtransmissions to mitigate interference between neighboring cells. Ingeneral, communication system 100 can provide a method to define andcapture interference constraints using both centralized and distributedICIC approaches that enable re-use one and FFR options for scheduling UEtransmissions. In addition, in certain embodiments, communication system100 can provide a method to enable resource adaptation for frequencydomain uplink ICIC that enables dynamic allocation and re-allocation ofsystem spectrum between re-use one and FFR frequencies for each cellradio in the system to optimize the sum of total utilities, as afunction of UE throughput rates, across all cells in the system or in agiven cluster.

In certain embodiments, the frequency spectrum for each cell can bedivided into four types of RBs. Each RB division can be represented by atwo-tuple representation indicating a maximum loT caused by aneighboring cell to a given and a maximum loT caused to a neighboringcell by the given cell. The division of frequency spectrum is bestunderstood by a schematic diagram illustrating the two-tuplerepresentation, which has been provided by FIG. 1B.

Referring to FIG. 1C, FIG. 1C is a simplified schematic diagramillustrating example details associated with an example frequencyspectrum 180 that can be associated with communication system 100 inaccordance with one potential embodiment of the communication system.Frequency spectrum 180 can represent the spectrum of frequencies acrossthe system bandwidth. As shown, frequency spectrum 180 can be dividedinto four types of RBs represented by two-tuples (L,L), (M,M), (H,L) and(L,H), each of which can be referred to herein as divisions or regionsof the frequency spectrum. In various embodiments, a fraction of thetotal resources (e.g., RBs) available for scheduling (e.g., based onsystem bandwidth) can be distributed among the RB divisions. A fractionof total resources that can be scheduled in the (L,L) region can berepresented as ‘ρ_(LL)’; a fraction of total resources that can bescheduled in the (M,M) region can be represented as ‘ρ_(MM)’; a fractionof total resources that can be scheduled in the (H,L) region can berepresented as ‘ρ_(HL)’; and a fraction of total resources that can bescheduled in the (L,H) region can be represented as ‘ρ_(LH)’.

It should be noted that the size and lay-out of the two-tuple divisionsillustrated in FIG. 1C are provided for illustrative purposes only andare not meant to limit the broad scope of the present disclosure. Itshould be understood that the frequency spectrum of any cell radio canbe divided into different RB regions, of varying size and/or order,depending on the deployment environment of a cell radio and/or anyneighboring cell radio. More specifically and as discussed in furtherdetail herein, the allocation and/or re-allocation of spectrum for oneor more cell radios for scheduling RBs can be dynamically adjusted incertain embodiments to optimize network UE throughput across all cellsin the network or in a given cluster.

The first indication in each two-tuple can represent the maximum loT(generally, interference) caused by one or more neighboring cellradio(s) toward the given serving cell radio (e.g., interference causedby cell radio 114 b toward cell radio 114 a) and the second indicationin each two-tuple can represent the maximum loT caused by the givenserving cell radio toward the one or more neighboring cell radio(s). Itshould be noted that the interference ‘caused by’ and ‘caused to’between neighboring cells is typically the interference PSD caused byuplink transmissions of UEs, in particular cell edge UEs, intended for agiven serving cell radio, which can cause interference betweenneighboring cells. For example, uplink transmissions of cell edge UE 112b intended for cell radio 114 a can cause interference towardsneighboring cell radio 114 b and uplink transmissions of cell edge UE112 c intended for cell radio 114 b can cause interference towardsneighboring cell radio 114 a.

Two-tuple (L,L) indicates a low interference caused by neighboringcell(s) for UEs (e.g., RBs for UEs) scheduled within the (L,L) regionand also a low interference caused to neighboring cell(s). The lowinterference can be associated with a low interference PSD guarantee(I_(LOW)), which may be considered an interference guarantee per RB thatmay be provided between neighboring cells by central management system122 such that each neighboring cell radio (e.g., cell radio 114 a-114 b)can schedule UE transmissions based, at least in part, on the lowinterference PSD guarantee (I_(LOW)). Thus, as referred to herein,I_(LOW) can be used as an interference PSD constraint that should be metby a given serving cell when scheduling UE transmissions such that, forany RB scheduled in various RB regions, the interference PSD toward anyneighboring cell(s) caused by a UE transmitting the associated RB shouldnot exceed the low interference PSD guarantee I_(LOW) as applicable forRBs having their own interference guarantees that are to be scheduled byany neighboring cell(s). In various embodiments, each cell radio 114a-114 b may seek to schedule cell edge UEs (e.g., RBs associated withcell edge UEs) that don't cause much interference PSD to one or moreneighboring cell(s) in the (L,L) region.

In certain embodiments, interference PSD caused to one or moreneighboring cell(s) by transmissions for a given UE can be determined bya given serving cell based on the number of uplink RBs assigned to theUE, the UE power control policy and the channel gain from the UE to oneor more neighboring cell(s). In certain embodiments, channel gain to oneor more neighboring cells can be estimated using RSRP measurements ofneighboring cell(s) reported by a given UE to its serving cell. Under anassumption of approximate uplink and downlink symmetry for transmissionsand under an assumption that the cell-specific reference signal (CRS)power for each of one or more neighboring cell(s) is known by theserving cell, RSRP measurements can, in certain embodiments, be used todetermine interference PSDs caused by UEs at neighboring cells

Accordingly, in various embodiments, UE 112 a-112 d can be configured toreport signal strength information, such as, for example, RSRP and/orRSRQ measurements for neighboring cells to a corresponding serving cell,which can be used to determine interference PSDs for each UE 112 a-112 dbased on the number of RBs assigned to the UEs. It is assumed, incertain embodiments, that central management system 122 can beconfigured to distribute the CRS for each cell radio 114 a-114 b amongthe cell radios to be used in determining interference PSDs for each UE112 a-112 d.

Moreover, under an assumption of uplink and downlink symmetry, thenumber of cell edge UEs for a particular serving cell that may bescheduled in the (L,L) can be determined using neighboring cell RSRPvalues reported by cell edge UEs for the serving cell. A furtherdiscussion of determining the number of cell edge UEs that can bescheduled in the (L,L) region is provided below with reference todiscussions related to determining fractions of resources for eachregion.

Two-tuple (M,M) indicates a medium interference caused by one or moreneighboring cell(s) for UEs scheduled within the (M,M) region and amedium interference caused to one or more neighboring cell(s). Themedium interference can be associated with a medium interference PSDguarantee (I_(MED)). In certain embodiments the medium interference PSDlevel (I_(MED)), can also be used as a constraint that should be met bya given serving cell when scheduling UE transmissions such that, for anyRB scheduled in various RB regions, the interference PSD toward anyneighboring cell(s) caused by a UE transmitting an associated RB shouldnot exceed the medium interference PSD I_(MED) as applicable for RBswith interference guarantees that are to be scheduled by the neighboringcell(s). In certain embodiments, each cell radio 114 a-114 b may seek toschedule most UEs (e.g., the RBs associated with the UEs) in the (M,M)region.

Two-tuple (H,L) indicates a high interference caused by one or moreneighboring cell(s) for UEs scheduled within the (H,L) region and a lowinterference caused to one or more neighboring cell(s). The highinterference can by associated with a high interference PSD (I_(HIGH)).In certain embodiments, each cell radio 114 a-114 b may seek to scheduleUEs that are close to it (e.g., interior UE 112 a associated withserving cell radio 114 a and interior UE 112 d associated with servingcell radio 114 b) in the (H,L) region.

Two-tuple (L,H) indicates a low interference caused by one or moreneighboring cell(s) for UEs scheduled within the (L,H) region and a highinterference caused to one or more neighboring cell(s). In certainembodiments, each cell radio 114 a-114 b may seek to schedule cell edgeUEs (e.g., UE 112 b and/or 112 c) that may cause high interference toone or more neighboring cell(s) in the (L,H) region.

In various embodiments, the (L,L) and (M,M) regions can be associatedwith re-use one frequencies of the frequency spectrum and the re-use onefrequencies can be re-used among neighboring cell radios for schedulinguplink UE transmissions. In various embodiments, the (H,L) and (L,H)regions can be associated with FFR frequencies of the frequencyspectrum, and the FFR frequencies can be distributed between neighboringcells for scheduling uplink UE transmissions according to the variousinterference PSD constraints I_(LOW) and I_(MED) associated with betweenneighboring cells such that interference guarantees for uplink RBtransmissions that are scheduled between neighboring cells do notviolate the I_(LOW) and I_(MED) PSD levels as provided by centralmanagement system 122.

In certain embodiments, distributed coloring for scheduling FFRresources between neighboring cells can be accomplished via HighInterference Indicator (HII) messages as defined in 3GPP standards,which can be exchanged between neighboring cells via the X2 interface toindicate which resources a given cell radio has scheduled or is seekingto schedule across certain frequencies. In various embodiments, HIImessages can be associated with a bitmap having coloring indicative ofthe RB guarantees provided between neighboring cells. For the HIImessages, in certain embodiments, only bits for RBs that are included inthe set of resources to be scheduled in the FFR region are coordinatedthrough HII, where bits for non-FFR RBs are ignored.

For example, in at least one embodiment, a convention can be adopted inwhich, if during operation a particular cell lowers its power andguarantees low interference on certain uplink RBs to be transmitted byUEs served by the particular cell, those RBs can be marked as ‘0’ whileothers are marked as ‘1’. Then, if a cell gets a message from aneighboring cell where both have high power and high interference causedto neighbors, but expect lower interference on the same RBs (e.g., foruplink RBs in the (L,H) region), then both neighboring cells can selecta new set of RBs with such characteristics from all sets of availableRBs, which have not been selected by each of their neighbors in the past(e.g., standard coloring) and determine uplink transmissions which meetthe I_(LOW) and I_(MED) guarantees in order to coordinate highinterference resource block (RB) guarantees and low interference RBguarantees for the FFR portion of the frequency spectrum.

In various embodiments, transmission power for UE 112 a-112 d for RBdivisions can be determined according to a power control algorithm thatcan be configured for cell radio 114 a-114 b. While the presentdisclosure addresses scheduling of resources and allocation of resourcesfor the frequency spectrum of each of one or more neighboring cells, UEpower control is not outside its broad and expansive scope. It isanticipated that this disclosure would indeed be applicable todetermining UE transmission power and a myriad of other alternatives,which may be associated with mitigating interference between one or moreneighboring cell(s), including macro cells and small cells, of a givencommunication system.

As noted previously, communication system 100 is configured to provide asystem and method to facilitate uplink ICIC in a network environmentthrough the use of information exchanges between each cell radio 114a-114 b and a central management entity (e.g., central management system122) and between each cell radio 114 a-114 b via the X2 interface. Thus,the system and method provided by communication system 100 can provide aframework of interference management in which coordination is partlycentralized (e.g., via central management system 122) to determine afraction of resources in the FFR region and interference PSD levels(e.g., interference guarantees I_(LOW) and I_(MED)) and is partlydistributed such that FFR patterns are determined in a distributedmanner between neighboring cells (e.g., via X2 exchanges) to coordinatehigh interference RB guarantees and low interference RB guarantees forthe FFR portion of the frequency spectrum. Accordingly, communicationsystem 100 provides a hybrid framework for centralized and distributedinterference mitigation coordination.

During operation, in various embodiments, each cell radio 114 a-114 bcan provide feedback information to central management system 122 thatcan include UE specific feedback and/or cell specific feedback relatedto path loss and/or interference at each UE served by each particularcell radio. Based, at least in part, on the feedback informationreceived from each cell radio 114 a-114 b, central management system 122can optimize one or more ICIC parameters to facilitate interferencemitigation between neighboring cell radios (e.g., cell radios 114 a-114b) of communication system 100 and can distribute the one or more ICICparameters to cell radios within the communication system. Upon receiptof the one or more ICIC parameters, each neighboring cell radio 114a-114 b can schedule for uplink UE transmissions (e.g., can schedule RBsfor UEs 112 a-112 d) for the re-use one portion of the spectrum based onthe ICIC parameters and can exchange HII messages via the X2 interfaceto schedule uplink UE transmissions for the FFR portion of the spectrumalso based on the ICIC parameters to provide uplink ICIC forcommunication system 100. Additional details related to the feedbackinformation received from cell radios and the optimized uplink ICICparameters provided to cell radios are provided in further detail below.

To begin, it should be noted that central management system 122 canoptimize the one or more uplink ICIC parameters based on receiving anyof: UE specific feedback alone from cell radios 114 a-114 b; cellspecific feedback alone from the cell radios 114 a-114 b; or anycombination of UE specific feedback and cell specific feedback from cellradios 114 a-114 b. In certain embodiments, a flag can be included inany feedback messages communicated to central management system 122indicating whether the feedback information is formatted as UE specificfeedback or cell specific feedback or both.

In various embodiments, UE specific feedback communicated to the centralmanagement system 122 from a given cell radio serving one or more UEscan include one or more of the following: the total number of UEsconnected to the serving cell radio and the total number of UEsconnected to the serving cell radio which have reported a neighboringcell radio signal strength (e.g., RSRP) above a particular threshold(e.g., a RSRP threshold); this number of UEs can generally identify thenumber of cell edge UEs for the serving cell radio. In at least oneembodiment, the threshold can be set based on the RSRP at the edge ofcoverage of cells and the minimum SINR that a network operator orservice provider desires to serve UEs. For example, the threshold couldbe set based on a formula such as‘RSRP_threshold=min_RSRP_at_coverage_edge−min_SINR’. For the set of UEsreporting neighboring cell signal strengths above the threshold, theserving cell can communicate to central management system 122 the signalstrength for the serving cell and a cell identifier (ID) andcorresponding signal strength for each neighboring cell determined to beabove the signal strength threshold. In certain embodiments, the cell IDcan be an evolved cell global identifier (ECGI) or a cell globalidentifier (CGI) as defined by 3GPP standards or can be a local cell ID.

During operation, central management system 122 can use the UE specificfeedback to determine interference received by and caused to each of oneor more cells neighboring each other and to determine a number ofneighbors for each cell for purposes of determining uplink ICICparameters that can be used in scheduling uplink UE transmissionsbetween neighboring cells for FFR portions of the system bandwidth.[Note, although the example operations discussed below are describedwith respect to RSRP, it should be understood that any signal strengthinformation could be used in a similar manner.] In general, the numberof neighbors that are determined for each cell will impact the fractionof FFR resources for the (L,H) region for scheduling cell edge UE(s) foreach cell such that the fraction of resources for this region may beinversely proportional to the number of neighbors that are considered tobe interferers for each cell. In various embodiments, cells can scheduletransmissions for the re-use one portion of the system bandwidth withoutinterference coordination among neighboring cells.

While UE specific feedback can be used to determine uplink ICICparameters, cell specific feedback can also be used, as described below.In certain embodiments, UE specific feedback may result in lessoperations being performed at each cell radio (e.g., cell radio 114a-114 b), for example, performing comparisons to a predetermined signalstrength threshold and including certain information in the UE specificfeedback where other operations can be offloaded to central managementsystem. Embodiments where UE specific feedback is provided may decreasethe computational impact on cell radios in communication system 100.However, if cell specific feedback may be used for the feedbackinformation, some of the processing for providing uplink ICIC can beabsorbed by the cell radios thereby freeing up more resources forcentral management system 122 to perform other operations. In addition,using cell specific feedback can reduce the load on the communicationlink between cell radios and the central management system.

In various embodiments, cell specific feedback communicated to thecentral management system 122 from a given cell radio serving one ormore UEs can include one or more ordered relative RSRP values (or othersimilar relative signal strength/interference values, determined in asimilar manner as relative RSRP values) for one or more neighboring cellradios of the serving cell radio. As noted previously relative RSRP orrelative interference can be determined by subtracting the serving cellRSRP as measured by a given UE a neighboring cell RSRP as measured bythe UE. Relative RSRP values or relative interference values, asreferred to interchangeably herein, can be used to determine neighboringcell radios for purposes of providing uplink ICIC for FFR portions ofthe system bandwidth. In certain embodiments, the one or more orderedrelative interference values (or, equally, ordered relative RSRP values)included cell specific feedback can be ordered in a descending orderaccording to a highest relative interference value determined for eachof one or more neighbors of the serving cell radio that is above apredetermined relative interference threshold, referred to herein as‘relativeInterf’.

Before describing operations associated with determining cell specificfeedback, it should be noted that although cell radios 114 a-114 b areillustrated in FIG. 1A as neighboring each other, it should beunderstood that any number of cell radios can be deployed incommunication system 100. As the number of cell radios could vary fromtens to hundreds to thousands, it is highly possible that not all cellradios would be considered neighbors of each other and resourceallocation between non-neighboring cells could be handled accordingly.In certain embodiments, a given cell radio (e.g., cell radio 114 a) candetermine whether one or more neighbors exist for the cell radio for thepurpose of mitigating interference between neighboring cells using RSRPand RSRQ measurements as reported by UEs served by the cell radio. Forcell neighbors that are determined to have a relative interference abovethe relativeInterf threshold, interference can be mitigated between theneighboring cells through coordinated scheduling of FFR portions of thesystem bandwidth using the uplink ICIC parameters provided by centralmanagement system 122 and through FFR exchanges (e.g., HII messagingbetween neighboring cells to schedule uplink transmissions for the FFRportion of the system bandwidth).

Generally, operations for determining and communicating ordered relativeinterference or relative RSRP values (or other similarinterference/signal strength information) for one or more neighboringcells can include: 1) at each of a given UE connected to a given servingcell radio, determining the RSRP for the serving cell and the RSRP foreach of one or more neighboring cells; 2) for each UE connected to theserving cell radio, calculating a relative interference value for eachreported neighbor, where the relative interference value (R) cangenerally be expressed as: R=neighboring cell RSRP—serving cell RSRP; 4)determining which of the relative interference values for each neighborare above a predetermined relative interference threshold, referred toherein as ‘relativeInterf’; 5) ordering the relative interference valuesabove the relative interference threshold in a descending order from alargest relative interference value; 5) determining a highest relativeinterference value for each cell neighbor above the threshold (e.g.,removing lower strength “duplicates” of cell neighbors) and 6) includingordered relative interference values for each highest cell neighborvalue in cell specific feedback communicated to central managementsystem 122.

In various embodiments, the ordered relative interference values can becommunicated as one or more ordered two-tuple pairs of (cell ID,relative interference) to central management system 122. In variousembodiments, the predetermined threshold relativeInterf can be set suchthat a cell can be determined as a neighboring cell for purposes offacilitating uplink ICIC between neighboring cells if it has an RSRPvalue that is at least equal to the serving cell RSRP plus some minimumrelative interference value (e.g., the relativeInterf threshold), say,for example, −5 dB. Additional details related to the cell specificfeedback and determining ordered sets of relative interference valuesfor a given serving cell can be best understood through an example usecase, which is provided below by FIG. 2.

As noted above, for the overall operation of communication system 100,central management system 122 can optimize one or more uplink ICICparameters to facilitate interference mitigation between neighboringcell radios (e.g., cell radios 114 a-114 b) of communication system 100based, at least in part, on the feedback information (e.g., UE specificfeedback information or cell specific feedback information) receivedfrom each cell radio 114 a-114 b, and can distribute the one or moreICIC parameters to cell radios within the communication system. Invarious embodiments, the one or more ICIC parameters can be used by eachcell radio 114 a-114 b as inputs for scheduling operations, linkadaptation operations and/or measurement reporting operations in orderto provide uplink ICIC for communication system 100 such thatneighboring cell radios 114 a-114 b provide interference guarantees forcertain uplink RBs for cell edge UEs served by each cell radio in orderto meet the low interference PSD level (I_(LOW)) and the mediuminterference PSD level (I_(MED)) as set by central management system 122for the FFR RB regions (H,L) and (L,H).

In various embodiments, the one or more ICIC parameters optimized bycentral management system 122 can include one or more of the following:the number of resources (e.g., RBs) that are to be scheduled in the FFRregion of the frequency spectrum for neighboring cell radios; whatfraction of resources that a cell radio can expect cause higherinterference to and receive lower interference from neighboring cell(s)(e.g., fraction of resources ρ_(LH) for scheduling cell edge UE(s); whatfraction of resources Σ_(LL), ρ_(MM), ρ_(HL) can be scheduled in the(L,L), (M,M) and (H,L) regions; a value for the low interference PSDlevel (I_(LOW)); and/or a value for the medium interference PSD level(I_(MED)).

In various embodiments, central management system 122 can determine thenumber of resources that are to be scheduled in the FFR region and thecorresponding fraction of resources for each RB region by solving asystem of equations. As noted, cell edge UEs which don't cause muchinterference PSD to neighboring cells can be scheduled in the (L,L)region. In certain embodiments, the fraction of resources ρ_(LL) to bescheduled in the (L,L) region can be determined from power controlparameters ‘ρ₀’ and ‘α’, as defined in 3GPP TS 36.214, as well as thenumber of users that need to be supported such that they causeinterference PSD less than I_(LOW)−3 dB or less at any neighboring cellbut are required to be scheduled with low interference PSD in order totransmit voice packets on 3 RBs. More generally, in at least oneembodiment, the fraction of resources ρ_(LL) to be scheduled in the(L,L) region can be calculated by determining for each cell edge UE, theinterference that the cell edge UE can tolerate on the uplink, and ifthis is less than I_(LOW) then the UE is considered to be scheduled inthe (L,L) region. The fraction of resources ρ_(LL) to be scheduled inthe (L,L) region can then be set based the number of cell edge UEs thatcan tolerate fit this characteristic and dividing by the total number ofUEs in the system.

In at least one embodiment, a first equation (Equation 1, shown below)can be used to relate the fraction of resources in ρ_(MM), ρ_(HL), andΣ_(LH) to the sum of the factions (e.g., 1, for the system bandwidth)and ρ_(LL), such that:ρ_(MM)+ρ_(HL)+ρ_(LH)=1−ρ_(LL)  Equation 1

In a similar manner, the number of resources per RB region can berelated to the total number of RBs available based on the systembandwidth. The number of RBs for the (L,L), (M,M), (L,H) and (H,L)regions, respectively, can be expressed as N_(RB) ^(LL), N_(RB) ^(MM),N_(RB) ^(LH), and N_(RB) ^(HL), respectively, with the total number ofRBs available for allocation being expressed as N_(RB) ^(TOT). Therelationship for number of RBs per region to the total number of RBsbased on system bandwidth can be expressed similar to Equation 1 and isshown in Equation 2, below such that:N _(RB) ^(MM) +N _(RB) ^(LH) +N _(RB) ^(HL) =N _(RB) ^(TOT) −N _(RB)^(LL)  Equation 2

In at least one embodiment, a second equation (Equation 3, shown below)can be used to relate ρ_(LH) and ρ_(HL) according to the number ofneighbors for each cell radio such that:ρ_(LH)/(ρ_(HL)+ρ_(LH))=1/(1+90th_percentile_num_neigh)  Equation 3

For equation 3, the ‘90th_percentile_num_neigh’ can be set to a valuecorresponding to approximately the 90th percentile of the number ofneighbors reported for each cell radio in communication system 100. Inat least one embodiment, the 90th percentile of a set reflects a valuesuch that 90 percent of the elements in the set are less than thisvalue. For example, say a first cell reports eight (8) neighbors, asecond cell reports six (6) neighbors, a third cell reports five (5)neighbors and a fourth cell reports (9) neighbors. In this example, the90th percentile number of neighbors would be between the third highestvalue (75th percentile) and the fourth highest value (100th percentile).As noted, the fraction of resources FFR resources for the (L,H) FFRregion may be inversely proportional to the number of neighborsconsidered as interferers for each cell.

In various embodiments, the number of neighbors for a given cell radio(e.g., cell radio 114 a) can be determined using UE specific feedbackand/or cell specific feedback. For example, in certain embodiments inwhich UE specific feedback is provided to central management system 122,the neighboring cell IDs and RSRPs reported by UEs above the neighboringcell RSRP threshold can be used to determine the number of neighbors forthe cell radio. In certain embodiments in which cell specific feedbackis provided to central management system 122, the number of neighborsreported for a given cell radio (e.g., cell radio 114 a) can bedetermined using the ordered relative RSRP values determined by the cellradio via RSRP and/or RSRQ values (or other signal strength/interferencevalues) reported by each UE served by the cell radio (e.g., UE 112 a-112b served by cell radio 114 a). In general, cell radios can be consideredneighbors of each other if at least one UE's transmit PSD on one RBexceeds the low interference PSD guarantee I_(LOW).

In at least one embodiment, a fourth equation (Equation 4, shown below)can be used to relate the FFR fraction of resources (e.g., ρ_(HL) forthe (H,L) region(s)+ρ_(LH) for the (L,H) region(s)) to the fraction ofresource ρ_(MM) in the (M,M) re-use one region as a ratio of resourceskappa ‘κ’ such that:κ=(ρ_(HL)+ρ_(LH))/ρ_(MM)  Equation 4

As described in further detail below, κ may depend on UE path loss (PL)to its serving cell and one or more interfering cells and can beoptimized to maximize a total some of utilities for UE throughput ratesfor certain interference PSD levels (e.g., constraints) I_(LOW), I_(MED)and a high interference PSD level (I_(HIGH)). The high interference PSDlevel (I_(HIGH)) is discussed in further detail below in reference tooptimization operations for κ. For purposes of the present discussion, κcan be assumed to be set to an initial nominal value based on thedeployment scenario of the cell radios for which UL ICIC is sought. Forexample, for a macro cell deployment, κ can be initially set to be in arange of approximately 0.15-0.2, which would mean less resources (e.g.,UEs) would be scheduled in the FFR region as there may likely be lesscell edge UEs for neighboring macro cells, and for a small celldeployment, κ can be initially set to be approximately 0.70, which wouldmean more resources (e.g., UEs) would be scheduled in the FFR region asthere may likely be more cell edge UEs for neighboring small cells.

Based on the determination of κ, the equations shown above, includingany combination of Equations 1-4, manipulations, estimations,derivations and/or generalizations which can be deduced therefrom andthe number of neighbors per cell radio, including any estimations,derivations and/or generalizations thereof (e.g., percentiles) can beused to determine the number of resources to be scheduled in the FFRregion of system bandwidth as well as the fraction of resources to bescheduled in each RB region.

Turning to the interference PSD levels I_(LOW) and I_(MED), in variousembodiments, central management system 122 can set the value for the lowinterference PSD level (I_(LOW)) to a highest value such that a highpercentage of UEs (e.g., approximately 90% or so) at cell edges canachieve an SINR in a range of approximately 5-7 dB when each UEtransmits over a predetermined number of RBs, for example one or twoRBs, using the power control parameters assigned to the correspondingUE. In some embodiments, I_(LOW) can be set at a level 5-10 dB lowerthan the downlink SINRs of cell edge UEs. In some embodiments, SINRs forcell edge UEs can be determined via relative RSRP values, either asreported in cell specific feedback to central management system or asdetermined by central management system 122 via UE specific feedback,which can be used to set I_(LOW) such that a high percentage of celledge UEs can achieve an SINR of approximately 5-7 dB for uplinktransmissions.

In various embodiments, central management system 122 can set the mediuminterference PSD level (I_(MED)) to be the interference averaged overall cell radios for all UEs connected thereto transmitting on one (orsome other low number) of RBs using their assigned power control. Forexample, the interference for all cell radios and all UEs served by thecell radios can be determined based on the relative RSRP valuesdetermined via UE specific or cell specific feedback. In certainembodiments, the high interference PSD level I_(HIGH) can be set to beequal to the high interference averaged over the FFR region (e.g., (H,L)and (L,H)) for all cells for all UEs transmitting on one (or some otherlow number) of RBs using their assigned power control.

As noted above, upon receipt of the one or more ICIC parameters, eachneighboring cell radio 114 a-114 b can begin to schedule uplink UEtransmissions (e.g., can schedule RBs for UEs 112 a-112 d) for there-use one and FFR regions of the system bandwidth (e.g., frequencyspectrum) based, at least in part, on the ICIC parameters received fromcentral management system 122 and/or through exchanges betweenneighboring cells (e.g., for FFR regions). In particular, in certainembodiments, neighboring cell radios can set higher or lowerinterference PSDs for RBs in order to meet the guarantees (e.g., the lowinterference PSD level I_(LOW) and medium interference PSD levelI_(MED)) as applicable for RBs with interference guarantees that are tobe scheduled between neighboring cell radios.

In various embodiments, neighboring cell radios 114 a-114 b can exchangeHII messages via the X2 interface to determine the specific resourcesthat each cell radio may schedule at one or more corresponding FFRfrequencies according to the ICIC parameters where only bits for RBsthat are to be scheduled in the FFR region are coordinated via the HIImessages with other bits being ignored. In general, the HII exchangesmay facilitate coordination of FFR resources for the FFR region (e.g.,(L,H) and (H,L)) such that each cell radio determined to be neighbors ofeach other for uplink ICIC purposes (e.g., cell radios 114 a-114 b) mayuse the interference guarantees for I_(LOW) and I_(MED) to setinterference levels on certain RBs, communicate the guarantees for thesecertain RBs to neighboring cells, and receive similar guarantees forother RBs scheduled by neighboring cells in order for each neighboringcell to schedule resources for UE served by each corresponding cell.

In essence, the system and method provided by communication system 100provides a hybrid combination of centralized and distributedinterference mitigation techniques using centralized exchanges betweeneach cell radio 114 a-114 b and central management system 122 anddistributed exchanges between neighboring cell radios (e.g., cell radios114 a-114 b) to provide uplink ICIC for the communication system.Accordingly, the system and method provided by communication system 100may provide one or more advantages, including but not limited to:providing a computationally simple method for providing interferencemitigation for uplink ICIC; requiring minimal overhead in informationalexchanges between cell radios and a central management system; providinga solution that is implementable in 3GPP Release 9 deployments; and/orproviding a solution to define and capture interference constraints toprovide for both re-use one and FFR options for scheduling UEtransmissions.

Additional features related to determining neighboring cells for aparticular serving cell based on relative interference or relative RSRPvalues for purposes of mitigating interference between neighboring cellscan best be understood through an example use case that includesmultiple cell radios associated with communication system 100, which isprovided below by FIG. 2.

Referring to FIG. 2, FIG. 2 is a simplified block diagram illustratingan example use case 200 for cell radios associated with communicationsystem 100 in accordance with one potential embodiment of the presentdisclosure. FIG. 2 includes central management system 122, a number ofcell radios 210-213, a number of UEs (UE1-UE3). Cell radios 210-213 canbe logically interconnected to each other via one or more correspondingX2 interfaces, which can be used to facilitate exchanges betweenneighboring cells to determine scheduling for specific resources in theFFR region of the system bandwidth. For example use case 200, cell radio210 is assumed to be serving and in communication with each of UE1-UE3via one or more sessions and UE1-UE3 are assumed to be configured toreport signal strength information, such as, for example, RSRPmeasurements for any serving or neighboring cells. Thus, cell radio 210can be referred to interchangeably using the terms ‘serving cell radio’or ‘serving cell’ for UE1-UE3 for purposes of describing featuresassociated with use case 200. Further, each cell radio 211-213 areassumed to be neighboring cell radios of serving cell radio 210 in ageographical sense for purposes of FIG. 2. However, as discussed belowfor FIG. 2, determination of a neighboring cell radio for purposes ofuplink ICIC in order to mitigate interference between neighboring cellscan be determined in at least one embodiment using cell specificfeedback that includes ordered relative interference values based onvarious UE measurements. Note, although the example operations forexample use case 200 are described with respect to RSRP, it should beunderstood that any signal strength/interference information could beused in a similar manner.

For purposes of example use case 200, assume UE1, UE2 and UE3 can bereferred to using the notation u₁, u₂ and u₃, respectively, and eachneighboring cell 211-213 can be referred to using the notation c₁, c₂and c₃, respectively. To begin, serving cell 210 may receive servingcell RSRP values from each of UE1, UE2 and UE3 via measurement reportingfrom each UE. The serving cell RSRP for UE1, UE2 and UE3, respectively,can be referred to using the notation Su₁, Su₂ and Su₃, respectively.

Serving cell 210 may also receive neighboring cell RSRP values from eachof UE1, UE2 and UE3 via measurement reporting from each UE. Neighboringcell RSRP values can be referred to using the notation Iu₁c₁, forexample, to indicate the neighboring cell RSRP as measured by UE1 fromneighboring cell c₁. Accordingly, serving cell 210 may receiveneighboring cell RSRP values: Iu₁c₁, Iu₁c₂, Iu₁c₃, Iu₂c₁, Iu₂c₂, Iu₂c₃,Iu₃c₁, Iu₃c₂, and Iu₃c₃ for each UE1-UE3 for each neighboring cell RSRPmeasurement value.

For each serving cell RSRP and each neighboring cell RSRP, serving cell210 can compute relative interference valuesRu_(i)c_(j)=Iu_(i)c_(j)−Su_(i) for each UE u_(i), where i=1, 2, 3 andeach neighboring cell c_(j), where j=1, 2, 3. Thus, in at least oneembodiment, relative interference values can be thought of asUE-neighbor cell pairs, e.g., a neighbor cell strength relative toserving cell strength as measured by a given UE served by the servingcell.

Upon computing relative interference values for each UE-neighbor cellpair, serving cell 210 can compare the calculated relative interferencevalues against a relative interference threshold (e.g., relativeInterf,as noted above) of say, for example, −5 dB. For all relativeinterference values above the threshold, serving cell 210 can order therelative interference values in descending order to determine thehighest relative interference values for each cell neighboring theserving cell. Say, for purposes of the present example, that followingthe threshold comparison and the ordering that serving cell 210determines that Ru₃c₂>Ru₂c₂>Ru₂c₁>Ru₂c₂>−5 dB.

From the ordering, serving cell 210 can determine that c₂ (cell radio212) is the strongest cell among all UE-neighbor cell pairs and itssignal strength is strongest at UE3 followed by UE2. Serving cell 210can further determine that c₁ (cell radio 211) is the cell with the nextstrongest cell among the UE-neighbor cell pairs and its signal strengthis strongest at UE2 followed by UE1. Serving cell 210 can furtherdetermine that all other relative interference values fall below the −5dB threshold for the remaining UE-neighbor cell pairs (e.g., therelative interference for cell radio 213 falls below the threshold).

For each neighbor having a relative interference value above therelativeInterf threshold, serving cell 210 can communicate cell specificinformation to management system 122 including, but not limited to, theRSRP for serving cell 210 ordered relative interference information foreach neighboring cell above the threshold. In certain embodiments, thereporting of ordered relative interference information can includecommunicating only the highest relative interference value as determinedfor each cell neighbor. For example, serving cell 210 may onlycommunicate Ru₃c₂ for cell radio 212 followed by Ru₂c₁ for cell radio211. In various embodiments, serving cell 210 can communicate therelative interference information as an ordered pair, including anidentity of a cell and its highest relative interference value. Forexample, serving cell 210 can communicate (cell ID2, Ru₃c₂) followed by(cell ID 1, Ru₂c₁) where cell ID2 and cell ID1 each identify neighboringcell radios 212 and 211, respectively.

Thus, as shown in the present example, although cell radio 213 mayneighbor cell radio 210, it may not be considered a neighboring cell forthe purposes of uplink ICIC for scheduling uplink transmissions forUE1-UE3. However, cell radio could still be considered a neighboringcell for uplink ICIC purposes for any UEs that may be served by cellradios 211 or 212.

Upon receiving the cell specific information, central management system122 can determine uplink ICIC parameters such as, for example, number ofresources in FFR, I_(LOW), I_(MED), and fractions including one or moreof ρ_(LL), ρ_(MM), ρ_(LH), and/or ρ_(HL), and can communicate the uplinkICIC parameters among all cell radios in the system. Each cell radio canschedule UEs (e.g., resources) according the parameters for both re-useone and FFR portions of the system bandwidth. For FFR scheduling, FFRexchanges (dash-dot lines) between neighboring cell radios 210, 211 and212 (e.g., neighboring for the purposes of mitigating uplinkinterference) can occur using one or more HII messages exchanged via theX2 interface to determine which UEs will be allocated to whichfrequencies using the uplink ICIC parameters received from centralmanagement system 122. The FFR exchanges may facilitate coordination ofFFR resources for the FFR region (e.g., (L,H) and (H,L)) such that eachcell radio determined to be neighbors of each other for uplink ICICpurposes (e.g., cell radios 210-212) may use the interference guaranteesfor I_(LOW) and I_(MED) to set interference levels on certain RBs,communicate the guarantees for these certain RBs to neighboring cells,and receive similar guarantees for other RBs scheduled by neighboringcells in order to schedule RBs for UE served by each corresponding cellin a manner that the interference guarantees promised for RBs, inparticular for cell edge UE transmissions, are not violated betweenneighboring cells.

Although no FFR exchanges may occur for cell radio 213 with regard toUE1-UE3 in the present example, FFR exchanges could occur for cell radio213 for any other UEs that could be served by any other cell radios thatmay cause interference to or receive interference from neighboringcell(s). However, even though cell radio 213 may not be involved in theFFR exchanges with regard to UE1-UE3, cell radio 213 would still providescheduling to any UEs that it may serve according to the uplink ICICparameters, particularly I_(LOW) and I_(MED), in order to not violateany RB guarantees that may be provided for any RBs for UE1-UE3.

Accordingly, as illustrated in example use case 200 that embodiments ofthe present disclosure can provide for a hybrid combination ofcentralized and distributed interference mitigation techniques usingcentralized exchanges between each cell radio and a central managemententity, which can determine fractions of FFR resources and interferencelevel guarantees for neighboring cell radios, and distributed exchangesbetween neighboring cell radios to provide uplink interferencemitigation for the communication system. It should be noted that theorder of operations with regard to comparisons against therelativeInterf threshold and ordering of relative interference valuescan be performed in any order. For example, in one embodiment thecomparison could be performed first, followed by the ordering. Inanother embodiment, for example, the ordering could be performed firstfollowed by the comparison. Thus, it should be understood that any orderof operations for any operations described herein could be performed inany order within the scope of the present disclosure.

Turning to FIG. 3, FIG. 3 is a simplified flow diagram illustratingexample operations 300 associated with providing uplink ICIC in anetwork environment in accordance with one potential embodiment ofcommunication system 100. In various embodiments, the operations can beperformed via a plurality of cell radios (e.g., cell radios 114 a-114 b)and central management system 122.

At any time, uplink transmissions can be scheduled for user equipmentconnected among one or more neighboring cells (e.g., cell radios 114a-114 b) of communication system 100. Accordingly, the operations canbegin at 302 in which one or more uplink ICIC parameters for multiplecells of the communication system can be determined by centralmanagement system based, at least in part, on feedback informationassociated with the cells. In certain embodiments, the feedbackinformation for the cells can be associated with signal strengthinformation (e.g., RSRP, CPICH Ec/Io, etc.) associated with the cells.In various embodiments, the RSRP information can include RSRPmeasurements for a serving cell and for one or more neighboring cellsreceived by the serving cell from each of one or more UE connected tothe serving cell. In various embodiments, the uplink ICIC parameters caninclude one or more of: a low interference PSD level (I_(LOW)), a mediuminterference PSD level (I_(MED)), a number of resources to be scheduledin FFR portions of the system bandwidth (e.g., frequency spectrum)available to the plurality of cells, and a fraction of total resourcesassociated with each of one or more resource block portions of thesystem bandwidth.

At 304, the operations can include communicating the uplink ICICparameters to each of the cells by central management system 122. At306, the operations can include exchanging interference informationbetween neighboring cells of the plurality of cells including, at leastin part, interference guarantees for uplink transmissions to bescheduled between each neighboring cell according to a low interferencePSD level (I_(LOW)) and a medium interference PSD level (I_(MED))included in the uplink ICIC parameters. In certain embodiments,neighboring cells for each of the plurality of cells can be determinedfrom signal strength information included in the feedback information bycomparing the signal strength information to a predetermined threshold(e.g., a relative interference threshold, a RSRP threshold, etc.). Incertain embodiments, the interference information can include HIImessages exchanged between neighboring cells for scheduling uplinktransmissions of user equipment for FFR portions of the system bandwidthavailable to the plurality of cells for scheduling uplink UEtransmissions.

At 308, the operations can include scheduling uplink transmissions(e.g., scheduling RBs to be transmitted) for UE served by theneighboring cells based, at least in part, on the uplink ICIC parametersand the interference information exchanged between neighboring cells. Incertain embodiments the uplink transmissions can be scheduled in bothre-use one and FFR portions of the system bandwidth. In variousembodiments, the operations can include communicating the scheduleduplink transmissions for the one or more UE (e.g., 112 a-112 d) servedby each cell radio to one or more UE via one or more uplink grantscommunicated to the UE. Accordingly, communication system 100 canprovides a hybrid combination of centralized and distributedinterference mitigation techniques using exchanges between each cellradio 114 a-114 b and central management system 122 and exchangesbetween neighboring cell radios (e.g., cell radios 114 a-114 b) toprovide uplink interference mitigation for the communication system.

Turning to FIG. 4, FIG. 4 is a simplified flow diagram illustratingexample operations 400 associated with determining UE specific feedbackfor a particular serving cell (e.g., cell radio 114 a serving UE 112a-112 b and/or cell radio 114 b serving UE 112 c-112 d), which can beused for uplink ICIC in accordance with one potential embodiment ofcommunication system 100. In various embodiments, operations 400 can beperformed by a given cell radio (e.g., cell radio 114 a, cell radio 114b) serving one or more UE (e.g., UE 112 a-112 d).

Prior to performing operations for determining UE specific feedback, theoperations can include enabling neighboring cell signal strengthmeasurement reporting (e.g., RSRP measurement reporting, RSRQmeasurement reporting, CPICH Ec/Io measurement reporting, etc.) at 402for UE(s) in communication system 100. At any time, uplink transmissionscan be scheduled for user equipment connected among one or more cellradios (e.g., cell radios 114 a-114 b) of communication system 100.Accordingly, at 404 the operations for determining UE specific feedbackcan include determining at a given serving cell (e.g., cell radio 114 a)a number of UE(s) connected to the serving cell. At 406, the operationscan include determining a number of UE(s) connected to the serving cellthat have reported one or more neighboring cell signal strength value(s)(e.g., RSRP, CPICH Ec/Io, etc.) above a predetermined threshold.

At 408, the operations can include determining if no neighboring cellsignal strength value(s) are above the threshold, for example,determining whether the number of UE(s) determined at 406 is equal tozero. If the number is equal to zero (e.g., there are no neighboringcell signal strength values above the threshold), the operations cancontinue to 410 in which the operations can involve including in UEspecific feedback information for the cell: the number of UE(s)connected to the cell and an indication that no UE(s) reportedneighboring cell signal strength value(s) above the threshold and theoperations may end. In certain embodiments, such an indication couldindicate to the serving cell and/or central management system 122 thatno FFR interference coordination may be needed for the UEs served by theserving cell. Instead, uplink transmission(s) for the UE(s) may bescheduled in the re-use one portion according the uplink ICICparameters, in particular, to satisfy I_(LOW) and I_(MED) so as not toviolate any RB guarantees provided to any neighboring cells.

If at 408, the operations determine that the number of UE(s) reportingone or more neighboring cell signal strength value(s) is not equal tozero, the operations can continue to 412. At 412, the operations caninvolve including in UE specific feedback information for the servingcell one or more of: (1) the number of UE(s) connected to the servingcell; (2) the number of UE(s) reporting one or more neighboring cellsignal strength value(s) above the threshold; and, (3) for each UEreporting one or more neighboring cell signal strength value(s) abovethe threshold, (a) the serving cell signal strength as reported by eachUE can be included in the UE specific feedback along with (b) each ofthe one or more neighboring cell signal strength value(s) above thethreshold as reported by each UE and a corresponding cell ID associatedwith each corresponding neighboring cell signal value included in the UEspecific feedback. In various embodiments, the UE specific feedback canbe communicated to central management system 122 to determine one ormore uplink ICIC parameters, as discussed herein.

Turning to FIG. 5, FIG. 5 is a simplified flow diagram illustratingexample operations 500 associated with determining cell specificfeedback for a particular serving cell (e.g., cell radio 114 a servingUE 112 a-112 b and/or cell radio 114 b serving UE 112 c-112 d), whichcan be used for uplink ICIC in accordance with one potential embodimentof communication system 100. In various embodiments, operations 500 canbe performed by a given cell radio (e.g., cell radio 114 a and/or cellradio 114 b) serving one or more UE (e.g., UE 112 a-112 d).

Prior to performing operations for determining cell specific feedback,the operations can include enabling neighboring cell signal strengthmeasurement reporting (e.g., RSRP measurement reporting, RSRQmeasurement reporting, CPICH Ec/Io measurement reporting, etc.) at 502for UE(s) in communication system 100. At any time, uplink transmissionscan be scheduled for user equipment connected among one or more cellradios (e.g., cell radios 114 a-114 b) of communication system 100.Accordingly, at 504 the operations for determining UE specific feedbackcan include determining relative interference value(s) for each of oneor more neighboring cell(s) of a given serving cell radio (e.g., cellradio 114 a) for each of one or more UE(s) connected to the servingcell. In certain embodiments, the operations at 504 assume a minimum ofone UE connected to the serving sell in order to determine the relativeinterference value(s) for one or more neighbor cell(s). In variousembodiments, each relative interference value can be determined bysubtracting the signal strength (e.g., RSRP, etc.) measured for theserving cell by a particular UE from a signal strength (e.g., RSRP,etc.) measured for a neighbor cell by the particular UE. Thus, eachrelative interference value can represent relative interference asdetermined for a UE-neighbor cell pair.

At 506, the operations can include comparing each relative interferencevalue to a predetermined relative interference threshold (e.g.,relativeInterf) to determine whether any relative interference value(s)that may be above the threshold. In certain embodiments, the relativeinterference threshold can be set to approximately −5 dB. At 508, theoperations can include determining if there are any relativeinterference value(s) above the threshold. If there are no relativeinterference values above the threshold, the operations can continue to510 in which the operations can involve including in the cell specificfeedback for the serving cell an indication that no relativeinterference value for any neighboring cell is above the threshold andthe operations may end. In certain embodiments, such an indication couldindicate to the serving cell and/or central management system 122 thatno FFR interference coordination may be needed for the UEs served by theserving cell. Instead, uplink transmission(s) for the UE(s) may bescheduled in the re-use one portion according the uplink ICICparameters, in particular, to satisfy I_(LOW) and I_(MED) so as not toviolate any RB guarantees provided to any neighboring cells.

If, however, the operations at 508 determine that there are any relativeinterference value(s) above the threshold, the operations can continueto 512 in which the operations can include ordering each of relativeinterference value above the threshold in a predetermined order. Incertain embodiments, the predetermined order can be a descending orderfrom the greatest relative interference to the lowest relativeinterference above the predetermined threshold. At 514, the operationscan include determining a highest relative interference value for eachneighboring cell above the threshold. At 516, the operations can involveincluding in the cell specific feedback information the highest relativeinterference value for each neighboring cell above the threshold and thecorresponding cell ID for the neighboring cell according to thepredetermined order. In various embodiments, the cell specific feedbackcan be communicated to central management system 122 to determine one ormore uplink ICIC parameters, as discussed herein.

Turning to FIGS. 6A-6C, FIGS. 6A-6C are simplified flow diagramsillustrating example operations associated with setting interferencepower spectral density (PSD) levels, which can be used to mitigateinterference between cell radios (e.g., cell radios 114 a-114 b) inaccordance with one potential embodiment of communication system 100.FIG. 6A is a simplified flow diagram illustrating example operations600A associated with setting a low interference PSD level I_(LOW) inaccordance with one embodiment of communication system 100. FIG. 6B is asimplified flow diagram illustrating example operations 600B associatedwith setting a medium interference PSD level I_(MED) in accordance withone embodiment of communication system 100. FIG. 6C is a simplified flowdiagram illustrating example operations 600C associated with setting ahigh interference PSD level I_(HIGH) in accordance with one potentialembodiment of communication system 100.

As discussed for the various embodiments described herein, the lowinterference PSD level I_(LOW) and the medium interference PSD levelI_(MED) can be used as constraints for scheduling uplink transmissionsfor UE in both re-use one and FFR portions of the system bandwidth forcell radios (e.g., cell radios 114 a-114 b) which can be deployed incommunication system 100. A high interference PSD level, while nottypically used as a constraint for scheduling uplink transmissions, canin various embodiments, be used in operations involved optimizing thefraction of resources that are to be scheduled in re-use one and FFRportions of the system bandwidth, which are described in further detailbelow with respect to discussions of kappa ‘κ’.

Referring to FIG. 6A for operations 600A associated with setting a lowinterference PSD level I_(LOW), the operations can include determiningat 610 SINR(s) for cell edge UE(s) served by cell radios incommunication system (e.g., cell radios 114 a-114 b). In variousembodiments, the determination of cell edge UEs and SINRs of the celledge UEs can be determined from the feedback information received fromthe cells. For example, RSRP values or other similar signal strengthvalues, which can included in UE specific feedback can be used todetermine relative RSRP values based on serving cell RSRP valuesincluded in the UE specific feedback. The relative RSRP values can bethen used to determine the SINRs of cell edge UEs. In another example,relative RSRP values or other similar signal strength values, which canbe included in cell specific feedback can also be used to determine theSINRs of cell edge UEs.

At 612, the operations can include setting the low interference PSDlevel I_(LOW) to a highest value such that a high percentage of celledge UEs can achieve a predetermined SINR when transmitting over apredetermined number of RB(s) using the power control parametersassigned to the UEs. In certain embodiments, the high percentage can beset to approximately 90% or more. In certain embodiments, thepredetermined number of RBs can be 1 or 2 RBs. In certain embodiments,the predetermined SINR for which the cell edge UEs are desired toachieve can be set within a range of approximately 5-7 dB and can beconfigured by a network operator and/or service provider. At 614, theoperations can involve including the low interference PSD level inuplink ICIC parameters, which can be communicated to the cell radios inthe system and the operations may end.

Referring to FIG. 6B for operations 600B associated with setting amedium interference PSD level I_(MED), in certain embodiments, theoperations assume that RSRP values (e.g., UE specific feedback) and/orrelative interference values (referred to interchangeable as relativeRSRP) values (e.g., cell specific feedback) have been communicated tocentral management system 122 by all cell radios (e.g., cell radios 114a-114 b) in communication system 100.

Accordingly, at 630, the operations can include determining an averageinterference for each cell in the system based on signal strength and/orrelative signal strength values received from each cell in the system(e.g., RSRP and/or relative RSRP). At 632, the operations can includecalculating an average of the average interference for all cell radiosin the system. At 634, the operations can include setting the mediuminterference PSD level equal to the average as calculated for all cellradios in the system. At 634, the operations can involve including themedium interference PSD level in uplink ICIC parameters, which can becommunicated back to the cell radios in the system.

Referring to FIG. 6C for operations 600C associated with setting a highinterference PSD level I_(HIGH), in certain embodiments, the operationsassume that RSRP values (e.g., UE specific feedback) and/or relativeinterference values (referred to interchangeable as relative RSRP)values (e.g., cell specific feedback) have been communicated to centralmanagement system 122 by all cell radios (e.g., cell radios 114 a-114 b)in communication system 100.

Accordingly, at 650 the operations can include determining the highestinterference values reported by each cell based on UE specific feedbackand/or cell specific feedback received from each cell radio in thesystem. In certain embodiments, the highest interference values for eachcell can include signal strength values that have been determined to beabove a predetermined signal strength threshold based on comparisonsperformed by each cell and/or relative signal strength values that havebeen determined to be above a relative signal strength threshold basedon comparisons performed by each cell. As the reported signal strengthor relative signal strength values are used to identify a number ofneighbors for each cell, these values can also generally be related withthe FFR region of the system bandwidth in which coordinated interferencemitigation can be provided for between neighboring cells. Accordingly,at 652 the operations can include calculating an average of the highestinterference vales for all cells in the system. At 654, the operationscan include setting the high interference PSD level to the calculatedaverage and the operations may end. In certain embodiments, such as, forexample, embodiments in which resource adaptation can be provided bycommunication system 100, the operations can involve including the highinterference PSD level in uplink ICIC parameters at 656 to becommunicated to the cells.

Turning to FIG. 7, FIG. 7 is a simplified flow diagram illustratingexample operations 700 associated with determining one or more uplinkICIC parameters including a number of resources to be scheduled in theFFR region of the frequency spectrum and determining fractions ofresources that are to be scheduled in various RB regions of thefrequency spectrum for providing uplink ICIC in accordance with onepotential embodiment of communication system 100. In variousembodiments, the operations can be performed via central managementsystem 122 based on feedback information received from one or more cellradios (e.g., cell radios 114 a-114 b) of communication system 100.

At any time, uplink transmissions can be scheduled for user equipmentconnected among one or more neighboring cells (e.g., cell radios 114a-114 b) of communication system 100. Accordingly, the operations canbegin at 702 in which a number of neighbors for each cell in the systemcan be determined based on feedback information received from the cellsin which the feedback information can include signal strengthinformation associated with the cells in communication system 100. Invarious embodiments, the feedback information can include UE specificfeedback information and/or cell specific feedback information, asdescribed herein.

At 704, the operations can include determining a high percentile of thenumber of neighbors for the cells. In various embodiments, the highpercentile can be a 90th percentile or more. At 706, the operations caninclude determining a number of resource blocks to be scheduled in the(H,L) and (L,H) regions combined (e.g., the FFR portion of the spectrum)and the fraction of resource blocks to be scheduled for the (H,L) region(ρ_(HL)), the fraction of resource blocks to be scheduled for the (L,H)region (ρ_(LH)), the fraction of resource blocks to be scheduled for the(M,M) region (ρ_(MM)) and the fraction of resource blocks to bescheduled for the (L,L) region (ρ_(LL)) using a system of equationsrelating the resource fractions, the system bandwidth and the highpercentile number of neighbors for the cells. In various embodiments,the system of equations can be any combination of Equations 1-4,discussed above, including any manipulations, estimations, derivationsand/or generalizations thereof to determine the number of RBs for the(H,L) and (L,H) regions (e.g., the FFR region) and the fraction ofresource blocks to be scheduled for each region. At 708, the operationscan involve including the number of RBs for the FFR region and one ormore of the fraction of RBs to be scheduled in each RB region in theuplink ICIC parameters, which can be communicated to the cell radios inthe system. In various embodiments as discussed herein, the low andmedium interference PSD levels can also be included in the uplink ICICparameters.

Accordingly, as illustrated in FIGS. 6A, 6B and 7 and as furtherdiscussed through various embodiments described herein, uplink ICICparameters can be provided to cell radios in communication system suchthat resource blocks can be scheduled between neighboring cell radios inboth re-use one portions and FFR portions of system bandwidth in orderto mitigate interference between neighboring cells. As noted previously,communication system 100 can also provide a method to enable resourceadaptation for frequency domain uplink ICIC to provide for the dynamicallocation and re-allocation of system bandwidth between re-use one andFFR frequencies for scheduling resources for each cell radio in thesystem in order to optimize the sum of total utilities, as a function ofUE throughput rates, across all cells in the system or in a givencluster of cells.

Referring to FIG. 8, FIG. 8 is a simplified schematic diagramillustrating other example details associated with another examplefrequency spectrum 800 that can be associated with communication system100 in accordance with one potential embodiment of the communicationsystem. Similar to example frequency spectrum 180 as shown in FIG. 1C,example frequency spectrum 800 can represent the spectrum of frequenciesacross the system bandwidth including four, two-tuple RB regions (L,L),(M,M), (H,L) and (L,H) with each region being associated with a fractionof resources ρ_(LL), ρ_(MM), ρ_(HL), and ρ_(LH), respectively. Examplefrequency spectrum 800 shown in FIG. 8 is similar in all respects toexample frequency spectrum 180 shown in FIG. 1C, except that additionalfeatures related to resource adaptation, which can be provided bycommunication system 100 in various embodiments, are also illustrated inFIG. 8.

For example, FIG. 8 illustrates that the portions of frequency spectrum800 allocated between re-use one frequencies and FFR frequencies can beadapted to maximize the sum of utilities for UE rates for all UEs (e.g.,UE 112 a-112 d) served by cell radios (e.g., cell radios 114 a-114 b) incommunication system 100. In various embodiments, resource adaptationbetween the re-use one frequencies and FFR frequencies can be providedby adapting the number of RBs that are to be scheduled in the (M,M) RBregion and the number of resources that are to be scheduled in the (L,H)RB region.

In various embodiments, communication system 100 can provide techniquesto maximize UE throughput rates for all UEs served by cell radios incommunication system 100 by adapting the fraction of resources that areto be scheduled in the (M,M) and (L,H) regions. Generally, the resourceadaptation techniques can include determining an optimal value of whichmaximizes UE throughput rates across all cell radios in thecommunication system for both interior UEs and cell edge UEs served bythe cell radios.

In various embodiments, determining an optimized value of κ can includeone or both of: (1) solving, by each cell radio, a low complexityoptimization problem for different values of κ based on a selectedutility function for UE throughput rates to determine an optimum valueof κ that maximizes total network performance across all cell radiosaccording to the selected utility function; and/or (2) determining, byeach cell radio for each UE served by the cell radio, a number of RBsassigned to UEs in each of the (M,M) and (L,H) regions in associationwith an expected MCS determined for each UE for the (M,M) regioncompared to a minimum MCS threshold and adapting the value of κ towardsan optimum value to maximize total network performance for UE throughputrates across all cell radios in the system.

As noted, the optimization problem can be associated with a selectedutility function. In various embodiments, a utility function for UErates can be expressed as U(r_(i)), where ‘i’ represents a UE index and‘r_(i)’ is an average throughput rate for the associated UE. In variousembodiments, the optimization may be solved to determine a maximum totalsum of utilities for UE rates U(r_(i)), which can be expresses as ‘max.Σ_(i)U(r_(i))’ for all UE in the system. In various embodiments, thechoice of utility function for the optimization problem can be selectedby a network operator or service provider according to a desired outcomerepresenting a tradeoff between fairness and system capacity.

In at least one embodiment, a total sum of a logarithmic function (LOG)of average UE throughput rates, which can be expressed as ‘Σ_(i)LOG(r_(i))’ for all UE in the system can be selected for the utilityfunction if the desire is to maximize fairness of average UE throughputrates versus system capacity. This utility function is typicallyreferred to as a proportional fair metric. In another embodiment, atotal sum of average UE throughput rates, which can be expressed as‘Σ_(i)(r_(i))’ can be selected for the utility function if the desire isto maximize average UE throughput rates. In another embodiment, a totalsum of weighted exponentials of average UE throughput rates, which canbe expressed as Σ_(i)(1/r_(i))^(m), can be selected if maximizingfairness of average UE throughput rates is most important. For theweighted exponentials utility function, increasing the value of ‘m’ canprovide for more fair (e.g., more equal) UE throughput rates. In atleast one embodiment, the utility function selected for optimizing κ caninclude maximizing the total sum of utilities for UE rates (e.g., max.Σ_(i)U(r_(i))) across all UEs for all cell radios in the system toprovide a tradeoff between fairness and capacity of total networkperformance. Thus, it should be understood that choice of utilityfunction can be varied based on the desires of a network operator and/orservice provider based on network fairness, capacity, throughput rates,combinations thereof or the like.

Accordingly, in certain embodiments, each cell radio can compute asolution to the optimization problem as represented as max.Σ_(i)U(r_(i)) using different values of κ for a selected utilityfunction, e.g., Σ_(i)U(r_(i))=Σ_(i) LOG(r_(i)),Σ_(i)U(r_(i))=Σ_(i)(1/r_(i))^(n), Σ_(i)U(r_(i))=Σ_(i)(r_(i)) or othersimilar utility function. The different values of κ for which utilityfor achievable UE rates can be evaluated by each cell radio can bereferred to herein as temporary values of κ. Generally during operationin at least one embodiment, each of a given cell radio of communicationsystem 100 can compute a total sum of achievable UE rates for all UEsserved by the cell radio using a weighted sum of each UEs rates for acorresponding temporary value of κ. For example, a given cell radio(e.g., cell radio 114 a) can calculate, in an iterative manner, a sum oftotal utility of UE rates for different temporary values of κ for allUEs (e.g., UE 112 a-112 b) served by the cell radio. As κ effects thenumber of RBs in the (M,M), (L,H) and (H,L) regions as illustrated bythe relationship shown in Equation 4, the utility of achievable UEthroughput rates for each UE served by the cell radio can vary dependingon the number of RBs allocated to each RB region.

For example, consider a certain temporary value of κ, which causes UEsserved by one particular cell radio to be starved for resources. Thiscould result in a low total sum of utility of UE throughput rates forthe cell radio for the corresponding temporary value of κ. In contrast,consider an example in which a particular temporary value of κ resultsin UEs served by the cell radio to achieve average UE throughput rates.This could result in an increased total sum utility of UE throughputrates for the cell radio for the corresponding temporary value of κ. Inthis manner, each cell radio in communication system 100 can calculate atotal sum of utility of UE throughput rates for different temporaryvalues of κ in various embodiments.

In at least one embodiment, upon calculating a sum of total utility forachievable UE rates across all the temporary values of κ, each cellradio (e.g., cell radio 114 a-114 b) can determine a maximum total sumof utility of UE throughput rates and an associated temporary value of κassociated thereto. In effect, each cell determines an optimal feasibleUE throughput rate for an optimal total sum of utility as a function ofκ. Note, as used herein in this Specification, the terms ‘effective’,‘feasible’ and ‘achievable’ can be used interchangeably in reference to‘UE rates’ or ‘UE throughput rates’, which can also be usedinterchangeably.

In certain embodiments, each cell radio can communicate the maximumtotal sum of utility and corresponding temporary value of κ to centralmanagement system 122. In certain embodiments, central management systemcan search maximum total sum of utilities for each cell radio and eachcorresponding temporary value of κ to determine the optimal utility oroptimal effective throughput rate for all UEs across all cell radios inorder to maximize total network performance. Upon determining theoptimal utility/optimal effective throughput rate for all UEs across allcell radios, central management system 122 can use the associatedtemporary value of κ to set the ratio of (ρ_(HL)+ρ_(LH))/ρ_(MM) in orderto determine corresponding uplink ICIC parameters that can then becommunicated to the cell radios so that they can schedule uplinktransmissions according to the uplink ICIC parameters. In variousembodiments, maximizing total network performance may, in effect,provide a technique to balance the allocation of the number of RBs foreach RB region such that no UEs receive all the resources for a cell orare starved for resources, thereby maximizing the total sum of utilitiesof UE throughput for communication system 100.

As an extension of the optimization operations discussed above, incertain embodiments, central management system 122 can determine varioustemporary values of κ (e.g., using UE specific feedback, cell specificfeedback, deployment information, etc.) and can distribute eachtemporary value of κ to cell radios 114 a-114 b to compute a total sumof utility of achievable or effective UE rates for the temporary valueof κ that can then be returned to central management system 122, whichcan update the value of κ accordingly based on a total sum of utilitiesreceived from the cell radios and can distribute a new temporary valueof κ to each cell radio 114 a-114 b to compute an updated total sum ofutility of achievable or effective throughput rates. Operations cancontinue in this manner until an optimal value of κ is found.

Illustrated below is a system of equations, Equations 5-12, which can beused to solve the optimization problem, in certain embodiments, tomaximize the total sum of utilities of UE throughput rates forcommunication system 100. Before detailing the equations, a briefdiscussion of various notations is provided. For example, neighboringcells are expressed as c₁, c₁, . . . , c_(M) for M neighboring cells; afraction of resources assigned to each UE i in each RB region areexpressed as α^(LL)(i), α^(MM) (i), α^(LH)(i) and α^(HL)(i) [note thatthese are represented as averages over multiple 1 msec intervals since,over a given subframe, the set of assigned RBs is contiguous]; path loss(in dB), which can be based on signal strength values (e.g., RSRP, RSRQ,etc.) from a UE i to a neighboring cell c_(i) as PL^(neigh)(i, j); afunction expressed as ‘ρ’, which maps SINR to spectral efficiency inbits/sec/Hz; open-loop power control parameters P₀ and α, as defined in3GPP TS 36.213, which are assumed to be the same for all UEs i fornotational convenience [note the transmit PSD for each UE=i isP₀+αPL^(serv)(i), assuming the UE has a small enough RB grant such thatit is not power limited]; and the number of RBs in each RB region can beexpressed, as noted above, as N_(RB) ^(LL), N_(RB) ^(MM), N_(RB) ^(LH),and N_(RB) ^(HL), which can be determined based on κ and the maximumnumber of neighbors per cell (or a percentile of the maximum number ofneighbors per cell) using one or more combinations of Equations 1-4, asdiscussed above.

In various embodiments, each cell radio (e.g., cell radio 114 a-114 b)can compute a solution the optimization problem of maximizing the totalthe sum utilities for achievable UE rates as characterized by theutility function, max. Σ_(i)U(r_(i)), for each UE served by the cellover α^(LL)(i), α^(MM)(i), α^(LH)(i), α^(HL)(i), ∀i based on theinterface PSDs I_(LOW), I_(HIGH) and I_(MED) which can be communicatedto each cell radio 114 a-114 b from central management system 122 forsolving the optimization problem.

In certain embodiments, a first set of equations for the optimizationproblem, Equations 5-8, shown below, can relate α^(LL)(i), α^(MM)(i),α^(LH)(i), α^(HL)(i), such that the total sum of fractions in each RBregion is equal to one across all UEs served by a particular cell radio.Σ_(i)α^(LL)(i)=1  Equation 5Σ_(i)α^(MM)(i)=1  Equation 6Σ_(i)α^(LH)(i)=1  Equation 7Σ_(i)α^(HL)(i)=1  Equation 8

In certain embodiments, a second set of equations for the optimizationproblem, Equations 9-11, shown below, provide constraints on the averageinterference PSD to each neighboring cell radio of a particular cellradio, where guarantees are made between neighboring cells to keepinterference below I_(LOW), I_(MED) or I_(HIGH). Recall, each UE indexis represented by i and each neighboring cell radio index is representedas j.Σ_(i)α^(LL)(i)(P ₀ +αPL ^(serv)(i)−PL ^(neigh)(i,j)≦I _(L) ,∀j  Equation9Σ_(i)α^(MM)(i)(P ₀ +αPL ^(serv)(i)−PL ^(neigh)(i,j)≦I _(M) ,∀j  Equation10Σ_(i)α^(HL)(i)(P ₀ +αPL ^(serv)(i)−PL ^(neigh)(i,j)≦I _(L) ,∀j  Equation11

In certain embodiments, another equation for the optimization problem,Equation 12, shown below can represent the feasible UE throughput foreach UE expressed as a weighted sum of throughput achievable by the UEin each RB region type (e.g., (L,L), (M,M), (L,H) and (H,L)) where thenumber of resource blocks that can be assigned to UEs in each region(M,M), (L,H) and (H,L) are effected by different temporary values of κ,as characterized by κ=(ρ_(HL)+ρ_(LH))/ρ_(MM) and additionalrelationships as can be determined and/or deduced from Equations 1-4,above. Accordingly, for each UE i, an effective rate can be determinedfrom Equation 12.r _(i) ≦[N _(RB) ^(LL)α^(LL)(i)ρ(P ₀ +αPL ^(serv)(i)−I _(L))+N _(RB)^(MM)α^(MM)(i)ρ(P ₀ +αPL ^(serv)(i)−I _(M))+N _(RB) ^(LH)α^(LH)(i)ρ(P ₀+αPL ^(serv)(i)−I _(H))+N _(RB) ^(HL)α^(LL)(i)ρ(P ₀ +αPL ^(serv)(i)−I_(L))],∀i  Equation 12

In certain embodiments, the optimal utility for each cell radio as afunction of κ can be expressed as U*_(c) _(n) (κ) for each cell radio‘n’ with the total effective UE rate for the cell radio being expressedas R*_(c) _(j) =U⁻¹(U*_(c) _(n) (κ)).

As noted above, an adaption of κ can also be provided by communicationsystem 100 in various embodiments, in which the value of κ can beincreased or decreased based on determining, by each cell radio for eachUE served by the cell radio, a number of RBs assigned to UEs in each ofthe (M,M) and (L,H) regions in association with an expected MCSdetermined for each UE for the (M,M) region compared to a minimum MCSthreshold and adapting the value of κ towards an optimum value tomaximize total network performance for UE throughput rates across allcell radios in the system.

Before detailing various operations associated with the adaptation of κ,consider a discussion of various use cases, which can exemplify variousreasons for adapting the value of κ. For example, consider a case inwhich there are lots of cell edge UEs served by cell radios 114 a-114 bof the communication system. In such a case, if the value of κ isincreased, then each cell radio would likely indicate an increase in thesum of utilities as increasing κ would allow for more RBs to beallocated in the FFR region (e.g., (H,L) and (L,H) through whichinterference for the cell edge UEs could be mitigated betweenneighboring cells via FFR exchanges for schedule UE uplinktransmissions. However, consider another case in which there are fewcell edge UEs served by cell radios 114 a-114 b. In this case,increasing the value of κ could result an increase in the sum ofutilities to a certain point and then it would begin to fall as moreinterior UEs, which may achieve higher throughput in the (M,M) region,would be unnecessarily scheduled in the FFR region as the number of RBsthat could be scheduled in the (M,M) region decreases with increasingvalues of κ.

Generally, the adaptation of κ, as facilitated by communication system100, can provide a technique to relate modulation and coding scheme(MCS) with SINR and UE throughput rate, as higher orders of MCS, whichcan be achieved at higher SINRs, can provide for higher UE throughputrates. In various embodiments, operations for adapting the value of κcan include each cell radio, for a current value of κ: (a) determiningan expected MCS for each UE in the (M,M) region when assigned a nominalnumber of RBs expressed as, N_(RB) ^(nom), say for example, 10, in orderto obtain a predetermined BLER for a first transmission, (b)(i)determining a first number of RBs, denoted as N_(RB) ^(low-MCS), whichrepresents the number of RBs that would be assigned to UEs in the (M,M)region having an expected MCS below a minimum MCS threshold, MCS^(MIN),averaged over a certain time period and (b)(ii) determining a secondnumber of RBs, denoted as N_(RB) ^(high-MCS), which represents thenumber of RBs assigned to UEs in the (L,H) region having an expected MCSabove MCS' averaged over a certain period of time. In variousembodiments, the period of time for averaging can range within a few(e.g., 1-3) seconds. In various embodiments, MCS^(MIN) can be associatedwith an MCS that might be selected by UEs having an SINR ofapproximately 5-10 dB. In various embodiments, the predetermined BLERcan be set to approximately 10%.

Each cell radio 114 a-114 b can feed back their corresponding values ofN_(RB) ^(low-MCS) and N_(RB) ^(high-MCS) to central management system122. In various embodiments, central management system 122 can determinea high percentile number of N_(RB) ^(low-MCS) RBs as reported in thecell radio feedback and can compare the high percentile to a firstthreshold. If the high percentile number of N_(RB) ^(low-MCS) RBs ishigher than the first threshold (e.g., indicating too many resources arebeing allocated to the (L,H) region), the current value of κ can bereduced. By reducing the current value of κ, UEs currently beingscheduled in the (L,H) region, which may actually be interior UEs notneeding coordinated interference mitigation (e.g., because not enoughresources are being allocated to the (M,M) region) and which mightresult in these UEs having little to no increase in SINR or possiblyeven a decrease in SINR by being scheduled in the (L,H) region, can bemoved to the (M,M) region to help maximize the sum of total utilities ofUE throughput for communication system 100. In at least one embodiment,the high percentile can be approximately the 90th percentile. In atleast one embodiment, the first (high) threshold can be set to theminimum SINR that a network operator or service provider desires toserve UEs plus a few (e.g., 1-2) dB, which can be expressed as‘high_threshold=min_SINR+few dB’.

Central management system 122 can also determine a low percentile numberof N_(RB) ^(high-MCS) RBs as reported in the cell radio feedback and cancompare the high percentile to a second threshold. If the low percentilenumber of N_(RB) ^(high-MCS) RBs is lower than the second threshold(e.g., indicating too few resources are being allocated to the (L,H)region), the current value of κ can be increased. By increasing thecurrent value of κ, UEs currently being scheduled in the (M,M) region,which may actually be cell edge UEs needing coordinated interferencemitigation (e.g., because not enough resources are being allocated tothe (L,H) region) and which might result in these UEs having a degradedSINR by being scheduled in the (M,M) region, can be moved to the (L,H)region to help maximize the sum of total utilities of UE throughput forcommunication system 100. In at least one embodiment, the second (low)threshold can be set to the minimum SINR that a network operator orservice provider desires to serve UEs minus a few (e.g., 1-2) dB, whichcan be expressed as ‘low_threshold=min_SINR−few dB’.

Accordingly, communication system 100 can provide a method to determinea value of κ and update the value of κ by solving a low complexityoptimization problem and/or providing an adaptation of the value of κ.Any combination of determining and/or updating the value of κ can beprovided within the scope of the present disclosure. For example, in atleast one embodiment the optimization problem can be solved to set thevalue of κ, which can thereafter be updated according to the adaptationoperations according to one or more predetermined time intervals or atone or more predetermined times. For example, the adaptation operationscould be triggered every hour, could be triggered at certain times ofthe day (e.g., to coincide with peak/minimal load periods), combinationsthereof or the like.

In another example, in at least one embodiment a nominal value of κ canbe set (e.g., depending on deployment scenario such as macro cell orsmall cell), which can thereafter be updated according to the adaptationoperations according to one or more predetermined time intervals or atone or more predetermined times. In another example, in at least oneembodiments, the optimization problem solved to determine an initialvalue of κ, which can thereafter be updated by re-solving theoptimization problem according to one or more predetermined timeintervals or at one or more predetermined times. Thus, it should beunderstood that any combination of determining or updating a value for κbased on a determined nominal value, a value determined by solving theoptimization problem and/or a value determined through adaptationoperations can be provided within the scope of the present disclosure.

Turning to FIG. 9, FIG. 9 is a simplified flow diagram illustratingexample operations 900 associated with providing resource adaptation forinterference mitigation in accordance with one potential embodiment ofthe communication system. In various embodiments, the operations can beperformed via central management system 122 and one or more cell radios(e.g., cell radios 114 a-114 b).

At any time, uplink transmissions can be scheduled for user equipment(e.g., UE 112 a-112 d) connected among one or more cells (e.g., cellradios 114 a-114 b) of communication system 100. Accordingly, theoperations can begin at 902 in which a ratio (e.g., κ) can be determinedrelating a first portion of a frequency spectrum in which FFR resourcesare to be assigned to a second portion of the frequency spectrum inwhich re-use one resources are to be assigned for one or more userequipment (e.g., UE 112 a-112 b) served by the cells. In certainembodiments, the first portion of the frequency spectrum can beassociated with (L,H) and (H,L) RB regions of the spectrum and thesecond portion can be associated with the (M,M) region of the spectrum.In various embodiments, determining the ratio can include setting avalue for the ratio to a nominal value based on a deploymentcharacteristic of the cell radios, solving the optimization problem byeach of the cell radios and determining a value of κ that maximizes atotal sum of utilities of UE throughput rates.

At 904, the operations can include updating the ratio relating the firstportion and the second portion of the frequency spectrum to optimizethroughput rates for the user equipment across the plurality of cellsand the operations may end. In various embodiments, updating the ratiocan include solving the optimization problem by each of the cell radiosand determining a value of κ that maximizes a total sum of utilities ofUE throughput rates and/or adapting the value of κ through variousadaptation operations to increase or decrease the value of κ based onvarious RB and/or MCS relationships, as discussed herein.

In certain embodiments, the operations can include waiting one or morepredetermined time intervals, one or more predetermined times,combinations thereof or the like at 906 and can repeat the updating(return to 904). In various embodiments, total network performance canbe maximized be determining and updating the ratio of resources to beallocated between the re-use one portions and FFR portions of thefrequency spectrum.

Turning to FIG. 10, FIG. 10 is a flow diagram illustrating exampleoperations 1000 associated with providing resource adaptation forinterference mitigation by solving an optimization problem to maximize atotal sum of utilities of UE throughput rates across all cell radios(e.g., cell radios 114 a-114 b) of communication system 100 inaccordance with one potential embodiment of communication system 100. Invarious embodiments, the operations can be performed via centralmanagement system 122 and one or more cell radios (e.g., cell radios 114a-114 b).

At any time, uplink transmissions can be scheduled for user equipment(e.g., UE 112 a-112 d) connected among one or more cells (e.g., cellradios 114 a-114 b) of communication system 100. Accordingly, theoperations can begin at 1002 in which each cell radio of thecommunication system can calculate a total sum of utilities ofachievable throughput rates for each UE served by the cell radio foreach of one or more values of κ for a utility function, e.g.,Σ_(i)U(r_(i))=Σ_(i) LOG(r_(i)),Σ_(i)U(r_(i))=Σ₁(1/r_(i))^(n), orΣ_(i)U(r_(i))=Σ_(i)(r_(i)). In various embodiments, the calculation canbe based on the optimization problem as described above via Equations5-12. In various embodiments, a given utility function can be selectedbased on the desires of a network operator and/or service provider,e.g., using a proportional fair metric, maximizing fairness, maximizingaverage throughput rate, combinations thereof or the like. With regardto the optimization problem, the one or more values of κ can be referredto as temporary values of κ.

At 1004, the operations can include communicating, by each cell radio,the total sum of utilities of achievable throughput for each value of κto central management system 122. In various embodiments, the results ofthe calculations can be communicated at the end of each calculation foreach value of κ or following the calculations for all values of κ. At1006, the operations can include calculating, by central managementsystem 122, a total sum of utilities of achievable throughput byaccumulating the values as reported by each cell radio for each value ofκ. At 1008, the operations can include determining a maximum total sumof utilities for a corresponding value of κ from the values reported toand accumulated by central management system. At 1010, the operationscan include setting the value κ that is to be used in determining uplinkICIC parameters (e.g., according to Equations 1-4, setting I_(LOW),I_(MED), etc. as discussed herein) to the corresponding value of κassociated with the maximized or optimum total sum of utilities for allcell radios and the operations may end.

Accordingly, communication system 100 can provide a method for settingand/or updating the value of κ by solving an optimization problem byeach cell radio and determining a maximum total sum of utilities ofachievable throughput across all cell radios in the communicationsystem.

Turning to FIG. 11, FIG. 11 is a flow diagram illustrating exampleoperations 1100 associated with providing resource adaptation forinterference mitigation through an adaptation of κ to maximize UEthroughput rates across all cell radios (e.g., cell radios 114 a-114 b)of communication system 100 in accordance with one potential embodimentof communication system 100. In various embodiments, the operations canbe performed via central management system 122 and one or more cellradios (e.g., cell radios 114 a-114 b).

At any time, uplink transmissions can be scheduled for user equipment(e.g., UE 112 a-112 d) connected among one or more cells (e.g., cellradios 114 a-114 b) of communication system 100. Accordingly, theoperations can begin at 1102 in which each cell radio may determine anexpected MCS for each user equipment served by the cell radio whenassigned a nominal number of RBs in order to obtain a predetermined BLERfor a first transmission by each UE served by the cell. In variousembodiments, the nominal number of RBs can be approximately 10 and thepredetermined BLER can be approximately 10%. However, it should beunderstood that these values can be adjusted accordingly within thescope of the present disclosure.

At 1104, the operations can include each cell determining a number ofRBs in the (M,M) region of the frequency spectrum (e.g., systembandwidth) assigned to user equipment having an expected MCS below aminimum MCS threshold. In various embodiments, the determination of thenumber of RBs in the (M,M) region having an expected MCS below theminimum MCS threshold can be performed after scheduling uplink UEtransmissions according to uplink ICIC parameters received from centralmanagement system 122. In various embodiments, the determination of thenumber of RBs in various regions (e.g., M,M) can be adapted in atime-scale of minutes, for example, ranging from approximately 1-60minutes. In various embodiments, the minimum MCS threshold can be set tothe MCS that is feasible at 5-10 dB.

At 1106, the operations can include each cell determining a number ofRBs in the (L,H) region of the frequency spectrum assigned to userequipment having an expected MCS above the minimum MCS threshold. Invarious embodiments, the determination can be averaged over a similartime frame as discussed for the operations at 1104. At 1108, theoperations can include reporting the number of RBs below/above theminimum MCS threshold for the (M,M) and (L,H) regions to centralmanagement system 122.

It should be noted that operations 1110, 1114, 1118 and 1122 andoperations 1112, 1116, 1120 and 1124 described for the remainder of FIG.11 can be performed in parallel with each other. At 1110, the operationscan include determining a low percentile number of RBs below the MCSthreshold as reported by the cell radios for the (M,M) region. Invarious embodiments, the low percentile number of RBs can correspond toapproximately the bottom 10th percentile of the number of RBs below theminimum MCS threshold as reported by the cell radios for the (M,M)region. At 1112, the operations can include determining a highpercentile number of RBs above the minimum MCS threshold as reported bythe cell radios for the (L,H) region. In various embodiments, the highpercentile number of RBs can correspond to approximately the top 90thpercentile of the number of RBs above the minimum MCS threshold asreported by the cell radios for the (L,H) region.

At 1114, the operations can include comparing the low RB percentilenumber to a low RB number threshold to determine at 1118 whether the lowpercentile number determined at 1110 is less than a low RB thresholdnumber of RBs. If so, the operations can continue to 1122 in which thevalue of κ can be increased and the operations can end. If not, theoperations can continue to 1126 in which no κ value changes are carriedout. At 1116, the operations can include comparing the high RBpercentile number of RBs to a high RB number threshold to determine at1120 whether the high RB percentile number of RBs is greater than thehigh RB number threshold. If so, the operations can include reducing thevalue of κ at 1124 and the operations may end. If not, the operationscan continue to 1126 in which no κ value changes are carried out.

Accordingly, communication system 100 can provide a method for updatingthe value of κ by performing an adaptation of κ using RB assignment andMCS comparison information reported by each cell radio in order tomaximize UE throughput across all cell radios by adjusting the ratio ofRBs that can be allocated between the re-use one and FFR regions of thefrequency spectrum.

Turning to FIGS. 12A-12C, FIGS. 12A-12C are simplified block diagramsillustrating example details of various elements that can be associatedwith communication system 100 in accordance with one or moreembodiments. FIG. 12A is a simplified block diagram illustrating exampledetails that can be associated with central management system 122 inaccordance with one embodiment of communication system 100. FIG. 12B isa simplified block diagram illustrating example details that can beassociated with cell radio 114 a in accordance with one embodiment ofcommunication system 100. FIG. 12C is a simplified block diagramillustrating example details that can be associated with UE 112 a inaccordance with one embodiment of communication system 100. AlthoughFIG. 12B describes features related to cell radio 114 a, it should beunderstood that the features as described for cell radio 114 a can alsobe provided with respect to cell radio 114 b. Similarly, although FIG.12C describes features related to UE 112 a, it should be understood thatthe features as described for UE 112 a can also be provided with respectto UE 112 b-112 d.

As shown in FIG. 12A, central management system 122 can includeinterference management module 150, a resource adaptation module 1202, acentral management storage 1204, a processor 1212 and a memory element1214. In at least one embodiment, processor 1212 is a hardware processorconfigured to execute various tasks, operations and/or functions ofcentral management system 122 as described herein and memory element1214 is configured to store data associated with central managementsystem 122. In at least one embodiment interference management module150 is configured to implement various interference mitigationoperations as described herein for central management system 122, suchas, for example, determining uplink ICIC parameters for cell radios 114a-114 b. In various embodiments, resource adaptation module 1202 isconfigured to implement various resource adaptation operations asdescribed herein for central management system 122, such as, forexample, setting and/or updating a value for κ according to theoptimization problem operations and/or updating a value of κ accordingthe adaptation operations as described herein. In various embodiments,central management storage 1204 can be configured to store informationassociated with various interference mitigation and/or resourceadaptation operations as described herein including, but not limited to,CRS power of cell radios in communication system 100, UE specificfeedback received from cell radios, cell specific feedback received fromcell radios, uplink ICIC parameters for cell radios, combinationsthereof or the like.

As shown in FIG. 12B, cell radio 114 a can include resource scheduler140 a, a transmitter 1240, a receiver 1242, one or more antenna(s) 1244,an interference mitigation module 1246, a cell radio storage 1248, aresource adaptation module 1250, a processor 1252 and a memory element1254. In at least one embodiment, processor 1252 is a hardware processorconfigured to execute various tasks, operations and/or functions of cellradio 114 a as described herein and memory element 1254 is configured tostore data associated with cell radio 114 a. In at least one embodiment,resource scheduler 140 a and interference mitigation module 1246 areconfigured to implement various resource scheduling operations asdescribed herein such as, for example, scheduling uplink transmissionsfor one or more UE (e.g., UE 112 a-112 b) in accordance with variousinterference mitigation operations, including, but not limited to, FFRexchanges via the X2 interface to coordinate uplink transmissions forthe FFR region of the frequency spectrum and/or scheduling re-use oneresources in the re-use one region of the frequency spectrum. In variousembodiments, resource scheduler 140 a can also be configured to scheduledownlink resources for transmitting downlink resources to one or moreUE. In at least one embodiment, resource adaptation module 1250 isconfigured to implement various resource adaptation operations asdescribed herein for cell radio 114 a, such as, for example, solving anoptimization problem, as described herein, to determine a total sum ofmaximized utilities of throughput rates for one or more UE (e.g., UE 112a-112 b) served by cell radio 114 a for a selected utility functionacross various temporary values of κ, communicating the maximizedutilities to central management system 122 and/or providing RBinformation associated with various MCS information, which can becommunicated to central management system 122. In various embodiments,cell radio storage 1248 can be configured to store informationassociated with various resource scheduling, interference mitigationand/or resource adaptation operations including, but not limited to, CRSpower of neighboring cell radios, UE specific and/or cell specificfeedback for communicating to central management system 122, uplink ICICparameters received from central management system 122, interferencemitigation FFR scheduling information obtained via HII messagesexchanged with neighboring cell radios, combinations thereof or thelike. In various embodiments, transmitter 1240 and receiver 1242 can beconnected to one or more antennas 1244 to facilitate the transmissionand/or reception of cellular data and/or information to/from one or moreUE (e.g., UE 112 a-112 b) served by cell radio 114 a using one or moreover-the-air control channels, data channels, combinations thereof orthe like as prescribed by 3GPP standards.

As shown in FIG. 12C, UE 112 a can include a user equipment scheduler1268, a transmitter 1260, a receiver 1262, one or more antenna(s) 1264,a user equipment storage 1270, a processor 1272 and a memory element1274. In at least one embodiment, processor 1272 is a hardware processorconfigured to execute various tasks, operations and/or functions of UE112 a as described herein and memory element 1274 is configured to storedata associated with UE 112 a. In at least one embodiment, userequipment scheduler 1268 is configured to implement various operationsas described herein such as, for example, preparing uplink transmissionsaccording to uplink grant(s) received from cell radio 114 a forscheduled uplink transmissions that can provide interference mitigationbetween one or more neighboring cell radios. In various embodiments,user equipment storage 1270 can be configured to store informationassociated with UE 112 a for the operation of UE 112 a. In variousembodiments, transmitter 1260 and receiver 1262 can be connected to oneor more antennas 1264 to facilitate the transmission and/or reception ofcellular data and/or information to/from one or more cell radios (e.g.,cell radio 114 a) using one or more over-the-air control channels, datachannels, combinations thereof or the like as prescribed by 3GPPstandards.

In regards to the internal structure associated with communicationsystem 100, each of UE 112 b-112 d and cell radio 114 b may each alsoinclude a respective processor and a respective memory element. Cellradio 114 b can additionally include one or more transmitters, receiversand/or antennas to facilitate over-the-air communications. Hence,appropriate software, hardware and/or algorithms are being provisionedin UEs 112 a-112 d, cell radios 114 a-114 b and central managementsystem 122 in order to facilitate interference mitigation and/orresource adaptation across cell radios 114 a-114 b of communicationsystem 100 using a hybrid of centralized and distributed interferencemitigation techniques for uplink UE transmissions. Note that in certainexamples, certain databases (e.g., for storing information associatedwith interference control and/or management for communication system100) can be consolidated with memory elements (or vice versa), or thestorage can overlap/exist in any other suitable manner.

In one example implementation, UE 112 a-112 d, cell radio 114 a-114 band central management system 122 are network elements, which are meantto encompass network appliances, servers, routers, switches, gateways,bridges, loadbalancers, firewalls, processors, modules, or any othersuitable device, component, element, or object operable to exchangeinformation that facilitates or otherwise helps coordinate interferencemitigation operations and/or resource adaptation operations (e.g., fornetworks such as those illustrated in FIGS. 1 and 2). In otherembodiments, these operations and/or features may be provided externalto these elements, or included in some other network device to achievethis intended functionality. Alternatively, one or more of theseelements can include software (or reciprocating software) that cancoordinate in order to achieve the operations and/or features, asoutlined herein. In still other embodiments, one or more of thesedevices may include any suitable algorithms, hardware, software,components, modules, interfaces, or objects that facilitate theoperations thereof. This may be inclusive of appropriate algorithms andcommunication protocols that allow for the effective exchange of data orinformation.

In various embodiments, UE 112 a-112 d, cell radios 114 a-114 b andcentral management system 122 may keep information in any suitablememory element [e.g., random access memory (RAM), read only memory(ROM), an erasable programmable read only memory (EPROM), applicationspecific integrated circuit (ASIC), etc.], software, hardware, or in anyother suitable component, device, element, or object where appropriateand based on particular needs. Any of the memory items discussed hereinshould be construed as being encompassed within the broad term ‘memoryelement’. The information being tracked or sent to UE 112 a-112 d, cellradio 114 a-114 b and central management system 122 could be provided inany database, register, control list, cache, or storage structure: allof which can be referenced at any suitable timeframe. Any such storageoptions may be included within the broad term ‘memory element’ as usedherein. Similarly, any of the potential processing elements, modules,and machines described herein should be construed as being encompassedwithin the broad term ‘processor’. Each of the network elements and userequipment can also include suitable interfaces for receiving,transmitting, and/or otherwise communicating data or information in anetwork environment. It should be noted that each cell radio 210-213, asshown in FIG. 2, can be configured similarly to each cell radio 114a-114 b, as shown in FIG. 1, in all respects with regard to theoperations, tasks and/or or functions described herein as well asincluding a respective processor, a respective memory element, arespective cell radio storage, a respective resource scheduler, arespective resource adaptation module, a respective transmitter, arespective receiver and one or more respective antenna(s) as describedherein.

Note that in certain example implementations, the interferencemitigation functions and/or resource adaptation functions as outlinedherein (e.g., for providing for uplink ICIC) may be implemented by logicencoded in one or more tangible media, which may be inclusive ofnon-transitory media (e.g., embedded logic provided in an ASIC, indigital signal processing (DSP) instructions, software [potentiallyinclusive of object code and source code] to be executed by a processor,or other similar machine, etc.). In some of these instances, memoryelements [as shown in FIGS. 12A-12C] can store data used for theoperations described herein. This includes the memory elements beingable to store software, logic, code, or processor instructions that areexecuted to carry out the activities described herein. A processor canexecute any type of instructions associated with the data to achieve theoperations detailed herein. In one example, the processors [as shown inFIGS. 12A-12C] could transform an element or an article (e.g., data,information) from one state or thing to another state or thing. Inanother example, the activities outlined herein may be implemented withfixed logic or programmable logic (e.g., software/computer instructionsexecuted by a processor) and the elements identified herein could besome type of a programmable processor, programmable digital logic (e.g.,a field programmable gate array (FPGA), a DSP processor, an EPROM, anelectrically erasable PROM (EEPROM) or an ASIC that includes digitallogic, software, code, electronic instructions, or any suitablecombination thereof.

Note that in this Specification, references to various features (e.g.,elements, structures, modules, components, steps, operations,characteristics, etc.) included in ‘one embodiment’, ‘exampleembodiment’, ‘an embodiment’, ‘another embodiment’, ‘certainembodiments’, ‘some embodiments’, ‘various embodiments’, ‘otherembodiments’, ‘alternative embodiment’, and the like are intended tomean that any such features are included in one or more embodiments ofthe present disclosure, but may or may not necessarily be combined inthe same embodiments. Note also that a module as used herein thisSpecification, can be inclusive of an executable file comprisinginstructions that can be understood and processed on a computer, and mayfurther include library modules loaded during execution, object files,system files, hardware logic, software logic, or any other executablemodules.

It is also important to note that the operations and steps describedwith reference to the preceding FIGURES illustrate only some of thepossible scenarios that may be executed by, or within, the system. Someof these operations may be deleted or removed where appropriate, orthese steps may be modified or changed considerably without departingfrom the scope of the discussed concepts. In addition, the timing ofthese operations may be altered considerably and still achieve theresults taught in this disclosure. The preceding operational flows havebeen offered for purposes of example and discussion. Substantialflexibility is provided by the system in that any suitable arrangements,chronologies, configurations, and timing mechanisms may be providedwithout departing from the teachings of the discussed concepts.

Note that with the examples provided above, as well as numerous otherexamples provided herein, interaction may be described in terms of one,two, three, or four network elements. However, this has been done forpurposes of clarity and example only. In certain cases, it may be easierto describe one or more of the functionalities by only referencing alimited number of network elements. It should be appreciated thatcommunication system 100 (and its teachings) are readily scalable andcan accommodate a large number of components, as well as morecomplicated/sophisticated arrangements and configurations. Accordingly,the examples provided should not limit the scope or inhibit the broadteachings of communication system 100 as potentially applied to a myriadof other architectures.

Although the present disclosure has been described in detail withreference to particular arrangements and configurations, these exampleconfigurations and arrangements may be changed significantly withoutdeparting from the scope of the present disclosure. For example,although the present disclosure has been described with reference toparticular communication exchanges involving certain network access andprotocols, communication system 100 may be applicable to other exchangesor routing protocols. Moreover, although communication system 100 hasbeen illustrated with reference to particular elements and operationsthat facilitate the communication process, these elements, andoperations may be replaced by any suitable architecture or process thatachieves the intended functionality of communication system 100.

Numerous other changes, substitutions, variations, alterations, andmodifications may be ascertained to one skilled in the art and it isintended that the present disclosure encompass all such changes,substitutions, variations, alterations, and modifications as fallingwithin the scope of the appended claims. In order to assist the UnitedStates Patent and Trademark Office (USPTO) and, additionally, anyreaders of any patent issued on this application in interpreting theclaims appended hereto, Applicant wishes to note that the Applicant: (a)does not intend any of the appended claims to invoke paragraph six (6)of 35 U.S.C. section 112 as it exists on the date of the filing hereofunless the words “means for” or “step for” are specifically used in theparticular claims; and (b) does not intend, by any statement in thespecification, to limit this disclosure in any way that is not otherwisereflected in the appended claims.

What is claimed is:
 1. A method comprising: determining a ratio relatinga first portion of a frequency spectrum in which fractional frequencyre-use (FFR) resources are to be assigned to a second portion of thefrequency spectrum in which re-use one resources are to be assigned,wherein the FFR resources and the re-use one resources are associatedwith uplink transmissions for a plurality of user equipment across aplurality of cells in a communication system; updating the ratiorelating the first portion and the second portion of the frequencyspectrum to optimize throughput rates for the plurality of userequipment across the plurality of cells, wherein at least one ofdetermining the ratio or updating the ratio includes maximizing a totalsum of utilities of throughput rates for the user equipment across theplurality of cells for a particular utility function, wherein themaximizing further comprises: calculating, by each cell of the pluralityof cells, a per cell total sum of utilities for achievable throughputrates for a plurality of user equipment served by each cell for each ofa plurality of possible values of the ratio; communicating, by each cellof the plurality of cells, the per cell total sum of utilities forachievable throughput rates to a central management system for each ofthe plurality of possible values of the ratio; calculating a total sumof utilities across the plurality of cells based on the per cell totalsum of utilities for each of the plurality of possible values of theratio; determining, by the central management system, a maximum totalsum of utilities and a particular value of the ratio associated with themaximum total sum of utilities; and setting the ratio equal to theparticular value of the ratio associated with the maximum total sum ofutilities; determining one or more uplink inter cell interferencecoordination (ICIC) parameters for the plurality of cells based on theratio; and scheduling uplink transmissions for user equipment served bythe plurality of cells based, at least in part, on the uplink ICICparameters.
 2. The method of claim 1, wherein the particular utilityfunction is based on one of: a total sum of a logarithmic function ofaverage throughput rates for the user equipment; a total sum of aweighted exponential function of average throughput rates for the userequipment; and a total sum of average throughput rates for the userequipment.
 3. The method of claim 1, wherein calculating the per celltotal sum of utilities for achievable throughput rates for the pluralityof user equipment served by a particular cell further comprises:calculating a weighted sum of throughput rates achievable for each userequipment served by the particular cell in relation to a number ofresource blocks that can be allocated in a plurality of resource blockregions of the frequency spectrum and wherein the number of resourceblocks that can be allocated in one or more of the resource blockregions is varied according to each of the plurality of possible valuesof the ratio; and accumulating weighted sums of throughput ratesachievable for all user equipment served by the particular cellaccording to each of the plurality of possible values of the ratio todetermine a total sum of utility of throughput rates for all userequipment served by the cell for each of the plurality of possiblevalues of the ratio.
 4. The method of claim 1, wherein updating theratio further comprises: determining, by each cell of the plurality ofcells, a first modulation and coding scheme (MCS) for each of aplurality of user equipment served by each cell in a first resourceblock region of the frequency spectrum.
 5. The method of claim 4,further comprising: determining, by each cell of the plurality of cells,a first number of resource blocks in the first resource block regionassigned to user equipment that have a corresponding first MCS below apredetermined MCS threshold; and determining, by each cell of theplurality of cells, a second number of resource blocks in a secondresource block region assigned to user equipment that have acorresponding first MCS above the predetermined MCS threshold.
 6. Themethod of claim 5, further comprising: communicating, by each cell ofthe plurality of cells, the first number of resource blocks and thesecond number of resource blocks to a central management system;increasing the ratio based on a determination that a low percentile ofthe first number of resource blocks communicated by each of theplurality of cells is below a first predetermined resource blockthreshold; and reducing the ratio based on a determination that a highpercentile of the second number of resource blocks communicated by eachof the plurality of cells is above a second predetermined resource blockthreshold.
 7. The method of claim 5, wherein the predetermined MCSthreshold is associated with a predeterminedsignal-to-interference-noise ratio (SINR) associated with interferencebetween neighboring cells of the plurality of cells in the communicationsystem.
 8. One or more non-transitory tangible media encoding logic thatincludes instructions for execution by a processor, wherein theexecution causes the processor to perform operations, comprising:determining a ratio relating a first portion of a frequency spectrum inwhich fractional frequency re-use (FFR) resources are to be assigned toa second portion of the frequency spectrum in which re-use one resourcesare to be assigned, wherein the FFR resources and the re-use oneresources are associated with uplink transmissions for a plurality ofuser equipment across a plurality of cells in a communication system;updating the ratio relating the first portion and the second portion ofthe frequency spectrum to optimize throughput rates for the plurality ofuser equipment across the plurality of cells, wherein at least one ofdetermining the ratio or updating the ratio includes maximizing a totalsum of utilities of throughput rates for the user equipment across theplurality of cells for a particular utility function, wherein themaximizing further comprises: calculating, by each cell of the pluralityof cells, a per cell total sum of utilities for achievable throughputrates for a plurality of user equipment served by each cell for each ofa plurality of possible values of the ratio; communicating, by each cellof the plurality of cells, the per cell total sum of utilities forachievable throughput rates to a central management system for each ofthe plurality of possible values of the ratio; calculating a total sumof utilities across the plurality of cells based on the per cell totalsum of utilities for each of the plurality of possible values of theratio; determining, by the central management system, a maximum totalsum of utilities and a particular value of the ratio associated with themaximum total sum of utilities; and setting the ratio equal to theparticular value of the ratio associated with the maximum total sum ofutilities; determining one or more uplink inter cell interferencecoordination (ICIC) parameters for the plurality of cells based on theratio; and scheduling uplink transmissions for user equipment served bythe plurality of cells based, at least in part, on the uplink ICICparameters.
 9. The media of claim 8, wherein calculating the per celltotal sum of utilities for achievable throughput rates for the pluralityof user equipment served by a particular cell further comprises:calculating a weighted sum of throughput rates achievable for each userequipment served by the particular cell in relation to a number ofresource blocks that can be allocated in a plurality of resource blockregions of the frequency spectrum and wherein the number of resourceblocks that can be allocated in one or more of the resource blockregions is varied according to each of the plurality of possible valuesof the ratio; and accumulating weighted sums of throughput ratesachievable for all user equipment served by the particular cellaccording to each of the plurality of possible values of the ratio todetermine a total sum of utility of throughput rates for all userequipment served by the cell for each of the plurality of possiblevalues of the ratio.
 10. The media of claim 8, wherein updating theratio further comprises: determining, by each cell of the plurality ofcells, a first modulation and coding scheme (MCS) for each of aplurality of user equipment served by each cell in a first resourceblock region of the frequency spectrum.
 11. The media of claim 10,wherein the execution causes the processor to perform furtheroperations, comprising: determining, by each cell of the plurality ofcells, a first number of resource blocks in the first resource blockregion assigned to user equipment that have a corresponding first MCSbelow a predetermined MCS threshold; and determining, by each cell ofthe plurality of cells, a second number of resource blocks in a secondresource block region assigned to user equipment that have acorresponding first MCS above the predetermined MCS threshold.
 12. Themedia of claim 11, wherein the execution causes the processor to performfurther operations, comprising: communicating, by each cell of theplurality of cells, the first number of resource blocks and the secondnumber of resource blocks to a central management system; increasing theratio based on a determination that a low percentile of the first numberof resource blocks communicated by each of the plurality of cells isbelow a first predetermined resource block threshold; and reducing theratio based on a determination that a high percentile of the secondnumber of resource blocks communicated by each of the plurality of cellsis above a second predetermined resource block threshold.
 13. The mediaof claim 8, wherein the particular utility function is based on one of:a total sum of a logarithmic function of average throughput rates forthe user equipment; a total sum of a weighted exponential function ofaverage throughput rates for the user equipment; and a total sum ofaverage throughput rates for the user equipment.
 14. The media of claim11, wherein the predetermined MCS threshold is associated with apredetermined signal-to-interference-noise ratio (SINR) associated withinterference between neighboring cells of the plurality of cells in thecommunication system.
 15. A system comprising: at least one memoryelement for storing data; and at least one processor for executinginstructions associated with the data, wherein the executing causes thesystem to perform operations, comprising: determining a ratio relating afirst portion of a frequency spectrum in which fractional frequencyre-use (FFR) resources are to be assigned to a second portion of thefrequency spectrum in which re-use one resources are to be assigned,wherein the FFR resources and the re-use one resources are associatedwith uplink transmissions for a plurality of user equipment across aplurality of cells in a communication system; updating the ratiorelating the first portion and the second portion of the frequencyspectrum to optimize throughput rates for the plurality of userequipment across the plurality of cells, wherein at least one ofdetermining the ratio or updating the ratio includes maximizing a totalsum of utilities of throughput rates for the user equipment across theplurality of cells for a particular utility function, wherein themaximizing further comprises: calculating, by each cell of the pluralityof cells, a per cell total sum of utilities for achievable throughputrates for a plurality of user equipment served by each cell for each ofa plurality of possible values of the ratio; communicating, by each cellof the plurality of cells, the per cell total sum of utilities forachievable throughput rates to a central management system for each ofthe plurality of possible values of the ratio; calculating a total sumof utilities across the plurality of cells based on the per cell totalsum of utilities for each of the plurality of possible values of theratio; determining, by the central management system, a maximum totalsum of utilities and a particular value of the ratio associated with themaximum total sum of utilities; and setting the ratio equal to theparticular value of the ratio associated with the maximum total sum ofutilities; determining one or more uplink inter cell interferencecoordination (ICIC) parameters for the plurality of cells based on theratio; and scheduling uplink transmissions for user equipment served bythe plurality of cells based, at least in part, on the uplink ICICparameters.
 16. The system of claim 15, wherein calculating the per celltotal sum of utilities for achievable throughput rates for the pluralityof user equipment served by a particular cell further comprises:calculating a weighted sum of throughput rates achievable for each userequipment served by the particular cell in relation to a number ofresource blocks that can be allocated in a plurality of resource blockregions of the frequency spectrum and wherein the number of resourceblocks that can be allocated in one or more of the resource blockregions is varied according to each of the plurality of possible valuesof the ratio; and accumulating weighted sums of throughput ratesachievable for all user equipment served by the particular cellaccording to each of the plurality of possible values of the ratio todetermine a total sum of utility of throughput rates for all userequipment served by the cell for each of the plurality of possiblevalues of the ratio.
 17. The system of claim 15, wherein updating theratio further comprises: determining, by each cell of the plurality ofcells, a first modulation and coding scheme (MCS) for each of aplurality of user equipment served by each cell in a first resourceblock region of the frequency spectrum.
 18. The system of claim 17,wherein the executing causes the system to perform further operations,comprising: determining, by each cell of the plurality of cells, a firstnumber of resource blocks in the first resource block region assigned touser equipment that have a corresponding first MCS below a predeterminedMCS threshold; and determining, by each cell of the plurality of cells,a second number of resource blocks in a second resource block regionassigned to user equipment that have a corresponding first MCS above thepredetermined MCS threshold.
 19. The system of claim 18, wherein theexecuting causes the system to perform further operations, comprising:communicating, by each cell of the plurality of cells, the first numberof resource blocks and the second number of resource blocks to a centralmanagement system; increasing the ratio based on a determination that alow percentile of the first number of resource blocks communicated byeach of the plurality of cells is below a first predetermined resourceblock threshold; and reducing the ratio based on a determination that ahigh percentile of the second number of resource blocks communicated byeach of the plurality of cells is above a second predetermined resourceblock threshold.
 20. The system of claim 19, wherein the predeterminedMCS threshold is associated with a predeterminedsignal-to-interference-noise ratio (SINR) associated with interferencebetween neighboring cells of the plurality of cells in the communicationsystem.